2279. Standard Electrode (Half-Cell) Potentials -
| $\mathrm{ClO}_{3}^{-}+3 \mathrm{H}_{3} \mathrm{O}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{HClO}_{2}+4 \mathrm{H}_{2} \mathrm{O}$ | +1.21 |
| $\mathrm{HClO}+\mathrm{H}_{3} \mathrm{O}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Cl}^{-}+2 \mathrm{H}_{2} \mathrm{O}$ | +1.482 |
| $\mathrm{HClO}+\mathrm{H}_{3} \mathrm{O}^{+}+\mathrm{e}^{-} \longrightarrow \frac{1}{2} \mathrm{Cl}_{2}+2 \mathrm{H}_{2} \mathrm{O}$ | +1.611 |
| $\mathrm{HClO}_{2}+2 \mathrm{H}_{3} \mathrm{O}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{HClO}+3 \mathrm{H}_{2} \mathrm{O}$ | +1.628 |
| $\mathrm{Co}^{3+}+\mathrm{e}^{-} \longrightarrow \mathrm{Co}^{2+}\left(2 \mathrm{~mol} / / \mathrm{H}_{2} \mathrm{SO}_{4}\right)$ | +1.83 |
| $\mathrm{Co}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Co}$ | -0.28 |
| $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}+\mathrm{e}^{-} \longrightarrow\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+}$ | +0.1 |
| $\mathrm{Co}(\mathrm{OH})_{3}+\mathrm{e}^{-} \longrightarrow \mathrm{Co}(\mathrm{OH})_{2}+\mathrm{OH}^{-}$ | +0.17 |


2279. Standard Electrode (Half-Cell) Potentials -
| $\mathrm{Co}(\mathrm{OH})_{3}+\mathrm{e}^{-} \longrightarrow \mathrm{Co}(\mathrm{OH})_{2}+\mathrm{OH}^{-}$ | +0.17 |
| $\mathrm{Cr}^{3}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Cr}$ | -0.744 |
| $\mathrm{Cr}^{3+}+\mathrm{e}^{-} \longrightarrow \mathrm{Cr}^{2+}$ | -0.407 |
| $\mathrm{Cr}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Cr}$ | -0.913 |
| $\left[\mathrm{Cu}(\mathrm{CN})_{2}\right]^{-}+\mathrm{e}^{-} \longrightarrow \mathrm{Cu}+2 \mathrm{CN}^{-}$ | -0.43 |
| $\mathrm{CrO}_{4}{ }^{2-}+4 \mathrm{H}_{2} \mathrm{O}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Cr}(\mathrm{OH})_{3}+5 \mathrm{OH}^{-}$ | -0.13 |
| $\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}+14 \mathrm{H}_{3} \mathrm{O}^{+}+6 \mathrm{e}^{-} \longrightarrow 2 \mathrm{Cr}^{3+}+21 \mathrm{H}_{2} \mathrm{O}$ | +1.232 |
| $\left[\mathrm{Cr}(\mathrm{OH})_{4}\right]^{-}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Cr}+4 \mathrm{OH}^{-}$ | -1.2 |


2279. Standard Electrode (Half-Cell) Potentials -
TABLE L1


2279. Standard Electrode (Half-Cell) Potentials -
| Half-Reaction | $E^{\circ}(\mathrm{V})$ |
| :---: | :---: |
| $\mathrm{Cr}(\mathrm{OH})_{3}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Cr}+3 \mathrm{OH}^{-}$ | -1.48 |
| $\mathrm{Cu}^{2+}+\mathrm{e}^{-} \longrightarrow \mathrm{Cu}^{+}$ | +0.153 |
| $\mathrm{Cu}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Cu}$ | +0.34 |
| $\mathrm{Cu}^{+}+\mathrm{e}^{-} \longrightarrow \mathrm{Cu}$ | $+0.521$ |
| $\mathrm{F}_{2}+2 \mathrm{e}^{-} \longrightarrow 2 \mathrm{~F}^{-}$ | +2.866 |
| $\mathrm{Fe}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Fe}$ | -0.447 |
| $\mathrm{Fe}^{3+}+\mathrm{e}^{-} \longrightarrow \mathrm{Fe}^{2+}$ | +0.771 |
| $\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}+\mathrm{e}^{-} \longrightarrow\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4-}$ | +0.36 |
| $\mathrm{Fe}(\mathrm{OH})_{2}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Fe}+2 \mathrm{OH}^{-}$ | -0.88 |
| $\mathrm{FeS}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Fe}+\mathrm{S}^{2-}$ | -1.01 |
| $\mathrm{Ga}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Ga}$ | -0.549 |
| $\mathrm{Gd}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Gd}$ | -2.279 |


2279. Standard Electrode (Half-Cell) Potentials -
| $\mathrm{Gd}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Gd}$ | -2.279 |
| $\frac{1}{2} \mathrm{H}_{2}+\mathrm{e}^{-} \longrightarrow \mathrm{H}^{-}$ | -2.23 |
| $2 \mathrm{H}_{2} \mathrm{O}+2 \mathrm{e}^{-} \longrightarrow \mathrm{H}_{2}+2 \mathrm{OH}^{-}$ | -0.8277 |
| $\mathrm{H}_{2} \mathrm{O}_{2}+2 \mathrm{H}_{3} \mathrm{O}^{+}+2 \mathrm{e}^{-} \longrightarrow 4 \mathrm{H}_{2} \mathrm{O}$ | +1.776 |
| $2 \mathrm{H}_{3} \mathrm{O}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{H}_{2}+2 \mathrm{H}_{2} \mathrm{O}$ | 0.00 |
| $\mathrm{HO}_{2}^{-}+\mathrm{H}_{2} \mathrm{O}+2 \mathrm{e}^{-} \longrightarrow 3 \mathrm{OH}^{-}$ | +0.878 |
| $\mathrm{Hf}^{4+}+4 \mathrm{e}^{-} \longrightarrow \mathrm{Hf}$ | -1.55 |
| $\mathrm{Hg}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Hg}$ | +0.851 |
| $2 \mathrm{Hg}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Hg}_{2}{ }^{2+}$ | +0.92 |
| $\mathrm{Hg}_{2}{ }^{2+}+2 \mathrm{e}^{-} \longrightarrow 2 \mathrm{Hg}$ | +0.7973 |
| $\left[\mathrm{HgBr}_{4}\right]^{2-}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Hg}+4 \mathrm{Br}^{-}$ | +0.21 |


2279. Standard Electrode (Half-Cell) Potentials -
| $\mathrm{Hg}_{2} \mathrm{Cl}_{2}+2 \mathrm{e}^{-} \longrightarrow 2 \mathrm{Hg}+2 \mathrm{Cl}^{-}$ | +0.26808 |


2279. Standard Electrode (Half-Cell) Potentials -
| Half-Reaction | $E^{\circ}(\mathrm{V})$ |
| :---: | :---: |
| $\left[\mathrm{Hg}(\mathrm{CN})_{4}\right]^{2-}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Hg}+4 \mathrm{CN}^{-}$ | -0.37 |
| $\left[\mathrm{HgI}_{4}\right]^{2-}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Hg}+4 \mathrm{I}^{-}$ | -0.04 |
| $\mathrm{HgS}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Hg}+\mathrm{S}^{2-}$ | -0.70 |
| $\mathrm{I}_{2}+2 \mathrm{e}^{-} \longrightarrow 2 \mathrm{I}^{-}$ | +0.5355 |
| $\mathrm{In}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{In}$ | -0.3382 |
| $\mathrm{K}^{+}+\mathrm{e}^{-} \longrightarrow \mathrm{K}$ | -2.931 |
| $\mathrm{La}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{La}$ | -2.52 |
| $\mathrm{Li}^{+}+\mathrm{e}^{-} \longrightarrow \mathrm{Li}$ | -3.04 |
| $\mathrm{Lu}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Lu}$ | $-2.28$ |
| $\mathrm{Mg}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Mg}$ | $-2.372$ |
| $\mathrm{Mn}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Mn}$ | -1.185 |


2279. Standard Electrode (Half-Cell) Potentials -
| $\mathrm{Mn}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Mn}$ | -1.185 |
| $\mathrm{MnO}_{2}+2 \mathrm{H}_{2} \mathrm{O}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Mn}(\mathrm{OH})_{2}+2 \mathrm{OH}^{-}$ | -0.05 |
| $\mathrm{MnO}_{4}^{-}+2 \mathrm{H}_{2} \mathrm{O}+3 \mathrm{e}^{-} \longrightarrow \mathrm{MnO}_{2}+4 \mathrm{OH}^{-}$ | +0.558 |
| $\mathrm{MnO}_{2}+4 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Mn}^{2+}+2 \mathrm{H}_{2} \mathrm{O}$ | +1.23 |
| $\mathrm{MnO}_{4}^{-}+8 \mathrm{H}^{+}+5 \mathrm{e}^{-} \longrightarrow \mathrm{Mn}^{2+}+4 \mathrm{H}_{2} \mathrm{O}$ | +1.507 |
| $\mathrm{Na}^{+}+\mathrm{e}^{-} \longrightarrow \mathrm{Na}$ | $-2.71$ |
| $\mathrm{Nd}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Nd}$ | -2.323 |
| $\mathrm{Ni}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Ni}$ | -0.257 |
| $\left[\mathrm{Ni}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Ni}+6 \mathrm{NH}_{3}$ | -0.49 |


2279. Standard Electrode (Half-Cell) Potentials -
| $\mathrm{NiO}_{2}+4 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Ni}^{2+}+2 \mathrm{H}_{2} \mathrm{O}$ | +1.593 |
| $\mathrm{NiO}_{2}+2 \mathrm{H}_{2} \mathrm{O}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Ni}(\mathrm{OH})_{2}+2 \mathrm{OH}^{-}$ | +0.49 |
| $\mathrm{NiS}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Ni}+\mathrm{S}^{2-}$ | +0.76 |
| $\mathrm{NO}_{3}{ }^{-}+4 \mathrm{H}^{+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{NO}+2 \mathrm{H}_{2} \mathrm{O}$ | +0.957 |
| $\mathrm{NO}_{3}{ }^{-}+3 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{HNO}_{2}+\mathrm{H}_{2} \mathrm{O}$ | +0.92 |


2279. Standard Electrode (Half-Cell) Potentials -
| Half-Reaction | $E^{\circ}(\mathrm{V})$ |
| :---: | :---: |
| $\mathrm{NO}_{3}{ }^{-}+\mathrm{H}_{2} \mathrm{O}+2 \mathrm{e}^{-} \longrightarrow \mathrm{NO}_{2}{ }^{-}+2 \mathrm{OH}^{-}$ | +0.10 |
| $\mathrm{Np}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Np}$ | -1.856 |
| $\mathrm{O}_{2}+2 \mathrm{H}_{2} \mathrm{O}+4 \mathrm{e}^{-} \longrightarrow 4 \mathrm{OH}^{-}$ | +0.401 |
| $\mathrm{O}_{2}+2 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{H}_{2} \mathrm{O}_{2}$ | +0.695 |
| $\mathrm{O}_{2}+4 \mathrm{H}^{+}+4 \mathrm{e}^{-} \longrightarrow 2 \mathrm{H}_{2} \mathrm{O}$ | +1.229 |
| $\mathrm{Pb}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Pb}$ | -0.1262 |
| $\mathrm{PbO}_{2}+\mathrm{SO}_{4}{ }^{2-}+4 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{PbSO}_{4}+2 \mathrm{H}_{2} \mathrm{O}$ | +1.69 |
| $\mathrm{PbS}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Pb}+\mathrm{S}^{2-}$ | -0.95 |
| $\mathrm{PbSO}_{4}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Pb}+\mathrm{SO}_{4}{ }^{2-}$ | -0.3505 |


2279. Standard Electrode (Half-Cell) Potentials -
| $\mathrm{PbSO}_{4}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Pb}+\mathrm{SO}_{4}{ }^{2-}$ | -0.3505 |
| $\mathrm{Pd}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Pd}$ | +0.987 |
| $\left[\mathrm{PdCl}_{4}\right]^{2-}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Pd}+4 \mathrm{Cl}^{-}$ | +0.591 |
| $\mathrm{Pt}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Pt}$ | +1.20 |
| $\left[\mathrm{PtBr}_{4}\right]^{2-}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Pt}+4 \mathrm{Br}^{-}$ | +0.58 |
| $\left[\mathrm{PtCl}_{4}\right]^{2-}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Pt}+4 \mathrm{Cl}^{-}$ | +0.755 |
| $\left[\mathrm{PtCl}_{6}\right]^{2-}+2 \mathrm{e}^{-} \longrightarrow\left[\mathrm{PtCl}_{4}\right]^{2-}+2 \mathrm{Cl}^{-}$ | +0.68 |
| $\mathrm{Pu}^{3}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Pu}$ | -2.03 |
| $\mathrm{Ra}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Ra}$ | -2.92 |
| $\mathrm{Rb}^{+}+\mathrm{e}^{-} \longrightarrow \mathrm{Rb}$ | -2.98 |
| $\left[\mathrm{RhCl}_{6}\right]^{3-}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Rh}+6 \mathrm{Cl}^{-}$ | +0.44 |


2279. Standard Electrode (Half-Cell) Potentials -
| $\left[\mathrm{RhCl}_{6}\right]^{3-}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Rh}+6 \mathrm{Cl}^{-}$ | +0.44 |
| $\mathrm{S}+2 \mathrm{e}^{-} \longrightarrow \mathrm{S}^{2-}$ | -0.47627 |
| $\mathrm{S}+2 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{H}_{2} \mathrm{~S}$ | +0.142 |
| $\mathrm{Sc}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Sc}$ | -2.09 |
| $\mathrm{Se}+2 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{H}_{2} \mathrm{Se}$ | -0.399 |
| $\left[\mathrm{SiF}_{6}\right]^{2-}+4 \mathrm{e}^{-} \longrightarrow \mathrm{Si}+6 \mathrm{~F}^{-}$ | -1.2 |


2279. Standard Electrode (Half-Cell) Potentials -
| Half-Reaction | $E^{\circ}(\mathrm{V})$ |
| :---: | :---: |
| $\mathrm{SiO}_{3}{ }^{2-}+3 \mathrm{H}_{2} \mathrm{O}+4 \mathrm{e}^{-} \longrightarrow \mathrm{Si}+6 \mathrm{OH}^{-}$ | -1.697 |
| $\mathrm{SiO}_{2}+4 \mathrm{H}^{+}+4 \mathrm{e}^{-} \longrightarrow \mathrm{Si}+2 \mathrm{H}_{2} \mathrm{O}$ | -0.86 |
| $\mathrm{Sm}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Sm}$ | -2.304 |
| $\mathrm{Sn}^{4+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Sn}^{2+}$ | +0.151 |
| $\mathrm{Sn}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Sn}$ | -0.1375 |
| $\left[\mathrm{SnF}_{6}\right]^{2-}+4 \mathrm{e}^{-} \longrightarrow \mathrm{Sn}+6 \mathrm{~F}^{-}$ | -0.25 |
| $\mathrm{SnS}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Sn}+\mathrm{S}^{2-}$ | -0.94 |
| $\mathrm{Sr}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Sr}$ | -2.89 |
| $\mathrm{TeO}_{2}+4 \mathrm{H}^{+}+4 \mathrm{e}^{-} \longrightarrow \mathrm{Te}+2 \mathrm{H}_{2} \mathrm{O}$ | +0.593 |
| $\mathrm{Th}^{4+}+4 \mathrm{e}^{-} \longrightarrow \mathrm{Th}$ | -1.90 |
| $\mathrm{Ti}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Ti}$ | -1.630 |


2279. Standard Electrode (Half-Cell) Potentials -
| $\mathrm{Ti}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Ti}$ | -1.630 |
| $\mathrm{U}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{U}$ | -1.79 |
| $\mathrm{V}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{V}$ | -1.19 |
| $\mathrm{Y}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Y}$ | -2.37 |
| $\mathrm{Zn}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Zn}$ | -0.7618 |
| $\left[\mathrm{Zn}(\mathrm{CN})_{4}\right]^{2-}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Zn}+4 \mathrm{CN}^{-}$ | -1.26 |
| $\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Zn}+4 \mathrm{NH}_{3}$ | -1.04 |
| $\mathrm{Zn}(\mathrm{OH})_{2}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Zn}+2 \mathrm{OH}^{-}$ | -1.245 |
| $\left[\mathrm{Zn}(\mathrm{OH})_{4}\right]^{2}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Zn}+4 \mathrm{OH}^{-}$ | -1.199 |
| $\mathrm{ZnS}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Zn}+\mathrm{S}^{2-}$ | -1.40 |
| $\mathrm{Zr}^{4}+4 \mathrm{e}^{-} \longrightarrow \mathrm{Zr}$ | -1.539 |


2281. Half-Lives for Several Radioactive Isotopes -
Half-Lives for Several Radioactive Isotopes


2281. Half-Lives for Several Radioactive Isotopes -
| Isotope | Half-Life ${ }^{1}$ | Type of Emission ${ }^{2}$ | Isotope | Half-Life ${ }^{3}$ | Type of Emission ${ }^{4}$ |
| :---: | :---: | :---: | :---: | :---: | :---: |
| ${ }_{6}^{14} \mathrm{C}$ | 5730 y | $\left(\beta^{-}\right)$ | ${ }_{83}^{210} \mathrm{Bi}$ | 5.01 d | $\left(\beta^{-}\right)$ |
| ${ }_{7}^{13} \mathrm{~N}$ | 9.97 m | $\left(\beta^{+}\right)$ | ${ }_{83}^{212} \mathrm{Bi}$ | 60.55 m | ( $\alpha$ or $\beta^{-}$) |
| ${ }_{9}^{15} \mathrm{~F}$ | $4.1 \times 10^{-22} \mathrm{~s}$ | (p) | ${ }_{84}^{210} \mathrm{Po}$ | 138.4 d | ( $)$ |
| ${ }_{11}^{24} \mathrm{Na}$ | 15.00 h | $\left(\beta^{-}\right)$ | ${ }_{84}^{212} \mathrm{Po}$ | $3 \times 10^{-7} \mathrm{~s}$ | ( $)$ |
| ${ }_{15}^{32} \mathrm{P}$ | 14.29 d | $\left(\beta^{-}\right)$ | ${ }_{84}^{216} \mathrm{Po}$ | 0.15 s | ( $)$ |
| ${ }_{19}^{40} \mathrm{~K}$ | $1.27 \times 10^{9} \mathrm{y}$ | ( $\beta$ or E.C.) | ${ }_{84}^{218} \mathrm{Po}$ | 3.05 m | ( $\alpha$ ) |


2281. Half-Lives for Several Radioactive Isotopes -
| ${ }_{26}^{49} \mathrm{Fe}$ | 0.08 s | $\left(\beta^{+}\right)$ | ${ }_{85}^{215} \mathrm{At}$ | $1.0 \times 10^{-4} \mathrm{~s}$ | ( $)$ |
| ${ }_{26}^{60} \mathrm{Fe}$ | $2.6 \times 10^{6} \mathrm{y}$ | $\left(\beta^{-}\right)$ | ${ }_{85}^{218} \mathrm{At}$ | 1.6 s | ( $)$ |
| ${ }_{27}^{60} \mathrm{Co}$ | 5.27 y | $\left(\beta^{-}\right)$ | ${ }_{86}^{220} \mathrm{Rn}$ | 55.6 s | ( $\alpha$ ) |
| ${ }_{37}^{87} \mathrm{Rb}$ | $4.7 \times 10^{10} \mathrm{y}$ | $\left(\beta^{-}\right)$ | ${ }_{86}^{222} \mathrm{Rn}$ | 3.82 d | ( $\alpha$ ) |
| ${ }_{38}^{90} \mathrm{Sr}$ | 29 y | $\left(\beta^{-}\right)$ | ${ }_{88}^{224} \mathrm{Ra}$ | 3.66 d | ( $)$ |
| ${ }_{49}^{115} \mathrm{In}$ | $5.1 \times 10^{15} \mathrm{y}$ | $\left(\beta^{-}\right)$ | ${ }_{88}^{226} \mathrm{Ra}$ | 1600 y | ( $\alpha$ ) |
| ${ }_{53}^{131} \mathrm{I}$ | 8.040 d | $\left(\beta^{-}\right)$ | ${ }_{88}^{228} \mathrm{Ra}$ | 5.75 y | $\left(\beta^{-}\right)$ |


2281. Half-Lives for Several Radioactive Isotopes -
| ${ }_{58}^{142} \mathrm{Ce}$ | $5 \times 10^{15} \mathrm{y}$ | ( $\alpha$ ) | ${ }_{89}^{228} \mathrm{Ac}$ | 6.13 h | $\left(\beta^{-}\right)$ |
| ${ }_{81}^{208} \mathrm{Tl}$ | 3.07 m | $\left(\beta^{-}\right)$ | ${ }_{90}^{228} \mathrm{Th}$ | 1.913 y | ( $\alpha$ ) |
| ${ }_{82}^{210} \mathrm{~Pb}$ | 22.3 y | $\left(\beta^{-}\right)$ | ${ }_{90}^{232} \mathrm{Th}$ | $1.4 \times 10^{10} \mathrm{y}$ | ( $\alpha$ ) |
| ${ }_{82}^{212} \mathrm{~Pb}$ | 10.6 h | $\left(\beta^{-}\right)$ | ${ }_{90}^{233} \mathrm{Th}$ | 22 m | $\left(\beta^{-}\right)$ |
| ${ }_{21}^{214} \mathrm{~Pb}$ | 26.8 m | $\left(\beta^{-}\right)$ | ${ }_{90}^{234} \mathrm{Th}$ | 24.10 d | $\left(\beta^{-}\right)$ |


2281. Half-Lives for Several Radioactive Isotopes -
[^18]2 E.C. = electron capture, S.F. = Spontaneous fission
$3 \mathrm{y}=$ years, $\mathrm{d}=$ days, $\mathrm{h}=$ hours, $\mathrm{m}=$ minutes, $\mathrm{s}=$ seconds


2281. Half-Lives for Several Radioactive Isotopes -
| Isotope | Half-Life ${ }^{1}$ | Type of Emission ${ }^{2}$ | Isotope | Half-Life ${ }^{3}$ | Type of Emission ${ }^{4}$ |
| :---: | :---: | :---: | :---: | :---: | :---: |
| ${ }_{83}^{206} \mathrm{Bi}$ | 6.243 d | (E.C.) | ${ }_{91}^{233} \mathrm{~Pa}$ | 27 d | $\left(\beta^{-}\right)$ |
| ${ }_{92}^{233} \mathrm{U}$ | $1.59 \times 10^{5} \mathrm{y}$ | ( $\alpha$ ) | ${ }_{96}^{242} \mathrm{Cm}$ | 162.8 d | ( $\alpha$ ) |
| ${ }_{92}^{234} \mathrm{U}$ | $2.45 \times 10^{5} \mathrm{y}$ | ( $\alpha$ ) | ${ }_{97}^{243} \mathrm{Bk}$ | 4.5 h | ( $\alpha$ or E.C.) |
| ${ }_{92}^{235} \mathrm{U}$ | $7.03 \times 10^{8} \mathrm{y}$ | ( $\alpha$ ) | ${ }_{99}^{253} \mathrm{Es}$ | 20.47 d | ( $\alpha$ ) |
| ${ }_{92}^{238} \mathrm{U}$ | $4.47 \times 10^{9} \mathrm{y}$ | ( $\alpha$ ) | ${ }_{100}^{254} \mathrm{Fm}$ | 3.24 h | ( $\alpha$ or S.F.) |
| ${ }_{92}^{239} \mathrm{U}$ | 23.54 m | $\left(\beta^{-}\right)$ | ${ }_{100}^{255} \mathrm{Fm}$ | 20.1 h | ( $\alpha$ ) |


2281. Half-Lives for Several Radioactive Isotopes -
| ${ }_{93}^{239} \mathrm{~Np}$ | 2.3 d | $\left(\beta^{-}\right)$ | ${ }_{101}^{256} \mathrm{Md}$ | 76 m | ( $\alpha$ or E.C.) |
| ${ }_{94}^{239} \mathrm{Pu}$ | $2.407 \times 10^{4} \mathrm{y}$ | ( $\alpha$ ) | ${ }_{102}^{254} \mathrm{No}$ | 55 s | ( $\alpha$ ) |
| ${ }_{94}^{239} \mathrm{Pu}$ | $6.54 \times 10^{3} \mathrm{y}$ | ( $\alpha$ ) | ${ }_{103}^{257} \mathrm{Lr}$ | 0.65 s | ( $\alpha$ ) |
| ${ }_{94}^{241} \mathrm{Pu}$ | 14.4 y | ( $\alpha$ or $\beta^{-}$) | ${ }_{105}^{260} \mathrm{Ha}$ | 1.5 s | ( $\alpha$ or S.F.) |
| ${ }_{95}^{241} \mathrm{Am}$ | 432.2 y | ( $\alpha$ ) | ${ }_{106}^{263} \mathrm{Sg}$ | 0.8 s | ( $\alpha$ or S.F.) |


2281. Half-Lives for Several Radioactive Isotopes -
TABLE M1


2283. Chapter 1 -
1. Place a glass of water outside. It will freeze if the temperature is below $0^{\circ} \mathrm{C}$.
2. (a) law (states a consistently observed phenomenon, can be used for prediction); (b) theory (a widely accepted explanation of the behavior of matter); (c) hypothesis (a tentative explanation, can be investigated by experimentation)
3. (a) symbolic, microscopic; (b) macroscopic; (c) symbolic, macroscopic; (d) microscopic
4. Macroscopic. The heat required is determined from macroscopic properties.
5. Liquids can change their shape (flow); solids can't. Gases can undergo large volume changes as pressure changes; liquids do not. Gases flow and change volume; solids do not.
6. The mixture can have a variety of compositions; a pure substance has a definite composition. Both have the same composition from point to point.
7. Molecules of elements contain only one type of atom; molecules of compounds contain two or more types of atoms. They are similar in that both are comprised of two or more atoms chemically bonded together.
8. Answers will vary. Sample answer: Gatorade contains water, sugar, dextrose, citric acid, salt, sodium chloride, monopotassium phosphate, and sucrose acetate isobutyrate.
9. (a) element; (b) element; (c) compound; (d) mixture; (e) compound; (f) compound; (g) compound; (h) mixture
10. In each case, a molecule consists of two or more combined atoms. They differ in that the types of atoms change from one substance to the next.
11. Gasoline (a mixture of compounds), oxygen, and to a lesser extent, nitrogen are consumed. Carbon dioxide and water are the principal products. Carbon monoxide and nitrogen oxides are produced in lesser amounts.
12. (a) Increased as it would have combined with oxygen in the air thus increasing the amount of matter and therefore the mass. (b) 0.9 g
13. (a) 200.0 g ; (b) The mass of the container and contents would decrease as carbon dioxide is a gaseous product and would leave the container. (c) 102.3 g


2283. Chapter 1 -
13. (a) 200.0 g ; (b) The mass of the container and contents would decrease as carbon dioxide is a gaseous product and would leave the container. (c) 102.3 g
14. (a) physical; (b) chemical; (c) chemical; (d) physical; (e) physical
15. physical
16. The value of an extensive property depends upon the amount of matter being considered, whereas the value of an intensive property is the same regardless of the amount of matter being considered.
17. Being extensive properties, both mass and volume are directly proportional to the amount of substance under study. Dividing one extensive property by another will in effect "cancel" this dependence on amount, yielding a ratio that is independent of amount (an intensive property).
18. about a yard
19. (a) kilograms; (b) meters; (c) meters/second; (d) kilograms/cubic meter; (e) kelvin; (f) square meters; (g) cubic meters
20. (a) centi-, $\times 10^{-2}$; (b) deci-, $\times 10^{-1}$; (c) Giga-, $\times 10^{9}$; (d) kilo-, $\times 10^{3}$; (e) milli-, $\times 10^{-3}$; (f) nano-, $\times 10^{-9}$; (g) pico-, $\times 10^{-12}$; (h) tera-, $\times 10^{12}$


2283. Chapter 1 -
21. (a) $\mathrm{m}=18.58 \mathrm{~g}, \mathrm{~V}=5.7 \mathrm{~mL}$. (b) $\mathrm{d}=3.3 \mathrm{~g} / \mathrm{mL}$ (c) dioptase (copper cyclosilicate, $\mathrm{d}=3.28-3.31 \mathrm{~g} / \mathrm{mL}$ ); malachite (basic copper carbonate, $\mathrm{d}=3.25-4.10 \mathrm{~g} / \mathrm{mL}$ ); Paraiba tourmaline (sodium lithium boron silicate with copper, $\mathrm{d}=2.82-3.32 \mathrm{~g} / \mathrm{mL}$ )
22. (a) displaced water volume $=2.8 \mathrm{~mL}$; (b) displaced water mass $=2.8 \mathrm{~g}$; (c) The block mass is 2.76 g , essentially equal to the mass of displaced water $(2.8 \mathrm{~g})$ and consistent with Archimedes' principle of buoyancy.
23. (a) $7.04 \times 10^{2}$; (b) $3.344 \times 10^{-2}$; (c) $5.479 \times 10^{2}$; (d) $2.2086 \times 10^{4}$; (e) $1.00000 \times 10^{3}$; (f) $6.51 \times 10^{-8}$; (g) $7.157 \times 10^{-3}$
24. (a) exact; (b) exact; (c) uncertain; (d) exact; (e) uncertain; (f) uncertain
25. (a) two; (b) three; (c) five; (d) four; (e) six; (f) two; (g) five
26. (a) 0.44 ; (b) 9.0 ; (c) 27 ; (d) 140 ; (e) $1.5 \times 10^{-3}$; (f) 0.44


2283. Chapter 1 -
27. (a) $2.15 \times 10^{5}$; (b) $4.2 \times 10^{6}$; (c) 2.08 ; (d) 0.19 ; (e) 27,440 ; (f) 43.0
28. (a) Archer X; (b) Archer W; (c) Archer Y
29. (a) $\frac{1.0936 \mathrm{yd}}{1 \mathrm{~m}}$; (b) $\frac{0.94635 \mathrm{~L}}{1 \mathrm{qt}}$; (c) $\frac{2.2046 \mathrm{lb}}{1 \mathrm{~kg}}$
30. $\frac{2.0 \mathrm{~L}}{67.6 \mathrm{fl} \mathrm{oz}}=\frac{0.030 \mathrm{~L}}{1 \mathrm{fl} \mathrm{oz}}$


2283. Chapter 1 -
Only two significant figures are justified.
61. $68-71 \mathrm{~cm} ; 400-450 \mathrm{~g}$
63. 355 mL
65. $8 \times 10^{-4} \mathrm{~cm}$
67. yes; weight $=89.4 \mathrm{~kg}$
69. $5.0 \times 10^{-3} \mathrm{~mL}$
71. (a) $1.3 \times 10^{-4} \mathrm{~kg}$; (b) $2.32 \times 10^{8} \mathrm{~kg}$; (c) $5.23 \times 10^{-12} \mathrm{~m}$; (d) $8.63 \times 10^{-5} \mathrm{~kg}$; (e) $3.76 \times 10^{-1} \mathrm{~m}$; (f) $5.4 \times 10^{-5}$ m ; (g) $1 \times 10^{12} \mathrm{~s}$; (h) $2.7 \times 10^{-11} \mathrm{~s}$; (i) $1.5 \times 10^{-4} \mathrm{~K}$
73. 45.4 L
75. $1.0160 \times 10^{3} \mathrm{~kg}$
77. (a) 394 ft ; (b) 5.9634 km ; (c) $6.0 \times 10^{2}$; (d) 2.64 L ; (e) $5.1 \times 10^{18} \mathrm{~kg}$; (f) 14.5 kg ; (g) 324 mg
79. $0.46 \mathrm{~m} ; 1.5 \mathrm{ft} / \mathrm{cubit}$
81. Yes, the acid's volume is 123 mL .
83. 62.6 in (about 5 ft 3 in .) and 101 lb


2283. Chapter 1 -
81. Yes, the acid's volume is 123 mL .
83. 62.6 in (about 5 ft 3 in .) and 101 lb
85. (a) $3.81 \mathrm{~cm} \times 8.89 \mathrm{~cm} \times 2.44 \mathrm{~m}$; (b) 40.6 cm
87. $2.70 \mathrm{~g} / \mathrm{cm}^{3}$
89. (a) 81.6 g ; (b) 17.6 g
91. (a) 5.1 mL ; (b) 37 L
93. $5371{ }^{\circ} \mathrm{F}, 3239 \mathrm{~K}$
95. $-23^{\circ} \mathrm{C}, 250 \mathrm{~K}$
97. $-33.4^{\circ} \mathrm{C}, 239.8 \mathrm{~K}$
99. $113{ }^{\circ} \mathrm{F}$


2284. Chapter 2 -
1. The starting materials consist of one green sphere and two purple spheres. The products consist of two green spheres and two purple spheres. This violates Dalton's postulate that that atoms are not created during a chemical change, but are merely redistributed.
2. This statement violates Dalton's fourth postulate: In a given compound, the numbers of atoms of each type (and thus also the percentage) always have the same ratio.
3. Dalton originally thought that all atoms of a particular element had identical properties, including mass. Thus, the concept of isotopes, in which an element has different masses, was a violation of the original idea. To account for the existence of isotopes, the second postulate of his atomic theory was modified to state that atoms of the same element must have identical chemical properties.
4. Both are subatomic particles that reside in an atom's nucleus. Both have approximately the same mass. Protons are positively charged, whereas neutrons are uncharged.
5. (a) The Rutherford atom has a small, positively charged nucleus, so most $\alpha$ particles will pass through empty space far from the nucleus and be undeflected. Those $\alpha$ particles that pass near the nucleus will be deflected from their paths due to positive-positive repulsion. The more directly toward the nucleus the $\alpha$ particles are headed, the larger the deflection angle will be. (b) Higher-energy $\alpha$ particles that pass near the nucleus will still undergo deflection, but the faster they travel, the less the expected angle of deflection.
(c) If the nucleus is smaller, the positive charge is smaller and the expected deflections are smaller-both in terms of how closely the $\alpha$ particles pass by the nucleus undeflected and the angle of deflection. If the nucleus is larger, the positive charge is larger and the expected deflections are larger-more $\alpha$ particles will be deflected, and the deflection angles will be larger. (d) The paths followed by the $\alpha$ particles match the predictions from (a), (b), and (c).
6. (a) ${ }^{133} \mathrm{Cs}^{+}$; (b) ${ }^{127} \mathrm{I}^{-}$; (c) ${ }^{31} \mathrm{P}^{3-}$; (d) ${ }^{57} \mathrm{Co}^{3+}$


2284. Chapter 2 -
7. (a) Carbon-12, ${ }^{12} \mathrm{C}$; (b) This atom contains six protons and six neutrons. There are six electrons in a neutral ${ }^{12} \mathrm{C}$ atom. The net charge of such a neutral atom is zero, and the mass number is 12 . (c) The preceding answers are correct. (d) The atom will be stable since C-12 is a stable isotope of carbon. (e) The preceding answer is correct. Other answers for this exercise are possible if a different element of isotope is chosen.
8. (a) Lithium- 6 contains three protons, three neutrons, and three electrons. The isotope symbol is ${ }^{6} \mathrm{Li}$ or ${ }_{3}^{6} \mathrm{Li}$.
(b) ${ }^{6} \mathrm{Li}^{+}$or ${ }_{3}^{6} \mathrm{Li}^{+}$
9. (a) Iron, 26 protons, 24 electrons, and 32 neutrons; (b) iodine, 53 protons, 54 electrons, and 74 neutrons
10. (a) 3 protons, 3 electrons, 4 neutrons; (b) 52 protons, 52 electrons, 73 neutrons; (c) 47 protons, 47 electrons, 62 neutrons; (d) 7 protons, 7 electrons, 8 neutrons; (e) 15 protons, 15 electrons, 16 neutrons


2284. Chapter 2 -
11. Let us use neon as an example. Since there are three isotopes, there is no way to be sure to accurately predict the abundances to make the total of 20.18 amu average atomic mass. Let us guess that the abundances are $9 \% \mathrm{Ne}-22,91 \% \mathrm{Ne}-20$, and only a trace of $\mathrm{Ne}-21$. The average mass would be 20.18 amu . Checking the nature's mix of isotopes shows that the abundances are $90.48 \% \mathrm{Ne}-20,9.25 \% \mathrm{Ne}-22$, and $0.27 \% \mathrm{Ne}-21$, so our guessed amounts have to be slightly adjusted.
12. 79.90 amu
13. Turkey source: $20.3 \%$ (of 10.0129 amu isotope); US source: $19.1 \%$ (of 10.0129 amu isotope)
14. The symbol for the element oxygen, $O$, represents both the element and one atom of oxygen. A molecule of oxygen, $\mathrm{O}_{2}$, contains two oxygen atoms; the subscript 2 in the formula must be used to distinguish the diatomic molecule from two single oxygen atoms.
15. (a) molecular $\mathrm{CO}_{2}$, empirical $\mathrm{CO}_{2}$; (b) molecular $\mathrm{C}_{2} \mathrm{H}_{2}$, empirical CH ; (c) molecular $\mathrm{C}_{2} \mathrm{H}_{4}$, empirical $\mathrm{CH}_{2}$; (d) molecular $\mathrm{H}_{2} \mathrm{SO}_{4}$, empirical $\mathrm{H}_{2} \mathrm{SO}_{4}$
16. (a) $\mathrm{C}_{4} \mathrm{H}_{5} \mathrm{~N}_{2} \mathrm{O}$; (b) $\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}$; (c) HO ; (d) $\mathrm{CH}_{2} \mathrm{O}$; (e) $\mathrm{C}_{3} \mathrm{H}_{4} \mathrm{O}_{3}$


2284. Chapter 2 -
17. (a) $\mathrm{CH}_{2} \mathrm{O}$; (b) $\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}$
18. (a) ethanol


2284. Chapter 2 -
(b) methoxymethane, more commonly known as dimethyl ether


2284. Chapter 2 -
(c) These molecules have the same chemical composition (types and number of atoms) but different chemical structures. They are structural isomers.
19. Use the molecular formula to find the molar mass; to obtain the number of moles, divide the mass of compound by the molar mass of the compound expressed in grams.
20. Formic acid. Its formula has twice as many oxygen atoms as the other two compounds (one each). Therefore, 0.60 mol of formic acid would be equivalent to 1.20 mol of a compound containing a single oxygen atom.
21. The two masses have the same numerical value, but the units are different: The molecular mass is the mass of 1 molecule while the molar mass is the mass of $6.022 \times 10^{23}$ molecules.
22. (a) $256.48 \mathrm{~g} / \mathrm{mol}$; (b) $72.150 \mathrm{~g} \mathrm{~mol}^{-1}$; (c) $378.103 \mathrm{~g} \mathrm{~mol}^{-1}$; (d) $58.080 \mathrm{~g} \mathrm{~mol}^{-1}$; (e) $180.158 \mathrm{~g} \mathrm{~mol}^{-1}$
23. (a) $197.382 \mathrm{~g} \mathrm{~mol}^{-1}$; (b) $257.163 \mathrm{~g} \mathrm{~mol}^{-1}$; (c) $194.193 \mathrm{~g} \mathrm{~mol}^{-1}$; (d) $60.056 \mathrm{~g} \mathrm{~mol}^{-1}$; (e) $306.464 \mathrm{~g} \mathrm{~mol}^{-1}$
24. (a) 0.819 g ;
(b) 307 g ;
(c) 0.23 g ;
(d) $1.235 \times 10^{6} \mathrm{~g}(1235 \mathrm{~kg})$;
(e) 765 g
25. (a) 99.41 g ;
(b) 2.27 g ;
(c) 3.5 g ;


2284. Chapter 2 -
(e) 765 g
25. (a) 99.41 g ;
(b) 2.27 g ;
(c) 3.5 g ;
(d) 222 kg ;
(e) 160.1 g
26. (a) 9.60 g ; (b) 19.2 g ; (c) 28.8 g
27. zirconium: $2.038 \times 10^{23}$ atoms; 30.87 g; silicon: $2.038 \times 10^{23}$ atoms; 9.504 g ; oxygen: $8.151 \times 10^{23}$ atoms; 21.66 g
28. $\mathrm{AlPO}_{4}: 1.000 \mathrm{~mol}$ or 26.98 g Al
$\mathrm{Al}_{2} \mathrm{Cl}_{6}: 1.994 \mathrm{~mol}$ or 53.74 g Al
$\mathrm{Al}_{2} \mathrm{~S}_{3}: 3.00 \mathrm{~mol}$ or 80.94 g Al
The $\mathrm{Al}_{2} \mathrm{~S}_{3}$ sample thus contains the greatest mass of Al.
29. $3.113 \times 10^{25} \mathrm{C}$ atoms
30. 0.865 servings, or about 1 serving.
31. $20.0 \mathrm{~g} \mathrm{H}_{2} \mathrm{O}$ represents the least number of molecules since it has the least number of moles.


2285. Chapter 3 -
1. The spectrum consists of colored lines, at least one of which (probably the brightest) is red.
2. 3.15 m
3. $3.233 \times 10^{-19} \mathrm{~J} ; 2.018 \mathrm{eV}$
4. $\nu=4.568 \times 10^{14} \mathrm{~s}^{-1} ; \lambda=656.3 \mathrm{~nm}$; Energy $\mathrm{mol}^{-1}=1.823 \times 10^{5} \mathrm{~J} \mathrm{~mol}^{-1}$; red
5. (a) $\lambda=8.69 \times 10^{-7} \mathrm{~m} ; E=2.29 \times 10^{-19} \mathrm{~J}$; (b) $\lambda=4.59 \times 10^{-7} \mathrm{~m} ; E=4.33 \times 10^{-19} \mathrm{~J}$; The color of (a) is red; (b) is blue.
6. $E=9.502 \times 10^{-15} \mathrm{~J} ; \nu=1.434 \times 10^{19} \mathrm{~s}^{-1}$
7. Red: $660 \mathrm{~nm} ; 4.54 \times 10^{14} \mathrm{~Hz} ; 3.01 \times 10^{-19} \mathrm{~J}$. Green: $520 \mathrm{~nm} ; 5.77 \times 10^{14} \mathrm{~Hz} ; 3.82 \times 10^{-19} \mathrm{~J}$. Blue: 440 nm ; $6.81 \times 10^{14} \mathrm{~Hz} ; 4.51 \times 10^{-19} \mathrm{~J}$. Somewhat different numbers are also possible.
8. $5.49 \times 10^{14} \mathrm{~s}^{-1}$; no
9. Quantized energy means that the electrons can possess only certain discrete energy values; values between those quantized values are not permitted.
10. 2.856 eV


2285. Chapter 3 -
9. Quantized energy means that the electrons can possess only certain discrete energy values; values between those quantized values are not permitted.
10. 2.856 eV
11. $-8.716 \times 10^{-18} \mathrm{~J}$
12. $-3.405 \times 10^{-20} \mathrm{~J}$
13. $33.9 \AA$
14. $1.471 \times 10^{-17} \mathrm{~J}$
15. Both involve a relatively heavy nucleus with electrons moving around it, although strictly speaking, the Bohr model works only for one-electron atoms or ions. According to classical mechanics, the Rutherford model predicts a miniature "solar system" with electrons moving about the nucleus in circular or elliptical orbits that are confined to planes. If the requirements of classical electromagnetic theory that electrons in such orbits would emit electromagnetic radiation are ignored, such atoms would be stable, having constant energy and angular momentum, but would not emit any visible light (contrary to observation). If classical electromagnetic theory is applied, then the Rutherford atom would emit electromagnetic radiation of continually increasing frequency (contrary to the observed discrete spectra), thereby losing energy until the atom collapsed in an absurdly short time (contrary to the observed long-term stability of atoms). The Bohr model retains the classical mechanics view of circular orbits confined to planes having constant energy and angular momentum, but restricts these to quantized values dependent on a single quantum number, $n$. The orbiting electron in Bohr's model is assumed not to emit any electromagnetic radiation while moving about the nucleus in its stationary orbits, but the atom can emit or absorb electromagnetic radiation when the electron changes from one orbit to another. Because of the quantized orbits, such "quantum jumps" will produce discrete spectra, in agreement with observations.


2285. Chapter 3 -
16. Both models have a central positively charged nucleus with electrons moving about the nucleus in accordance with the Coulomb electrostatic potential. The Bohr model assumes that the electrons move in circular orbits that have quantized energies, angular momentum, and radii that are specified by a single quantum number, $n=1,2,3, \ldots$, but this quantization is an ad hoc assumption made by Bohr to incorporate quantization into an essentially classical mechanics description of the atom. Bohr also assumed that electrons orbiting the nucleus normally do not emit or absorb electromagnetic radiation, but do so when the electron switches to a different orbit. In the quantum mechanical model, the electrons
do not move in precise orbits (such orbits violate the Heisenberg uncertainty principle) and, instead, a probabilistic interpretation of the electron's position at any given instant is used, with a mathematical function $\psi$ called a wavefunction that can be used to determine the electron's spatial probability distribution. These wavefunctions, or orbitals, are three-dimensional stationary waves that can be specified by three quantum numbers that arise naturally from their underlying mathematics (no ad hoc assumptions required): the principal quantum number, $n$ (the same one used by Bohr), which specifies shells such that orbitals having the same $n$ all have the same energy and approximately the same spatial extent; the angular momentum quantum number 1 , which is a measure of the orbital's angular momentum and corresponds to the orbitals' general shapes, as well as specifying subshells such that orbitals having the same $l$ (and $n$ ) all have the same energy; and the orientation quantum number $m$, which is a measure of the $z$ component of the angular momentum and corresponds to the orientations of the orbitals. The Bohr model gives the same expression for the energy as the quantum mechanical expression and, hence, both properly account for hydrogen's discrete spectrum (an example of getting the right answers for the wrong reasons, something that many chemistry students can sympathize with), but gives the wrong expression for the angular momentum (Bohr orbits necessarily all have non-zero angular momentum, but some quantum orbitals [ $s$ orbitals] can have zero angular momentum).


2285. Chapter 3 -
17. $n$ determines the general range for the value of energy and the probable distances that the electron can be from the nucleus. $l$ determines the shape of the orbital. $m_{1}$ determines the orientation of the orbitals of the same $l$ value with respect to one another. $m_{s}$ determines the spin of an electron.
18. (a) $2 p$; (b) $4 d$; (c) $6 s$
19. (a) $3 d$; (b) 1 s ; (c) $4 f$
20.


2285. Chapter 3 -
41. (a) x. 2, y. 2, z. 2; (b) x. 1, y. 3, z. 0 ; (c) x. $400 \frac{1}{2}$, y. $210 \frac{1}{2}$, z. $320 \frac{1}{2}$; (d) x. 1, y. 2 , z. 3 ; (e) $x . l=0, m_{l}=0$, y. $l=1, m_{l}=-1,0$, or +1, z. $l=2, m_{l}=-2,-1,0,+1,+2$
43. 12
45.

| $n$ | $I$ | $m_{I}$ | $s$ |
| :---: | :---: | :---: | :---: |
| 4 | 0 | 0 | $+\frac{1}{2}$ |
| 4 | 0 | 0 | $-\frac{1}{2}$ |
| 4 | 1 | -1 | $+\frac{1}{2}$ |
| 4 | 1 | 0 | $+\frac{1}{2}$ |
| 4 | 1 | +1 | $+\frac{1}{2}$ |
| 4 | 1 | -1 | $-\frac{1}{2}$ |


2285. Chapter 3 -
47. For example, $\mathrm{Na}^{+}: 1 s^{2} 2 s^{2} 2 p^{6}$; $\mathrm{Ca}^{2+}: 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6}$; $\mathrm{Sn}^{2+}: 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6} 4 d^{10} 5 s^{2}$; $\mathrm{F}^{-}$: $1 s^{2} 2 s^{2} 2 p^{6} ; \mathrm{O}^{2-}: 1 s^{2} 2 s^{2} 2 p^{6} ; \mathrm{Cl}^{-}: 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6}$.
48. (a) $1 s^{2} 2 s^{2} 2 p^{3}$; (b) $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{2}$; (c) $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{2} 3 d^{6}$; (d)
```
$1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{2} 3 d^{10} 4 p^{6} 5 s^{2} 4 d^{10} 5 p^{4}$; (e) $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{2} 3 d^{10} 4 p^{6} 5 s^{2} 4 d^{10} 5 p^{6} 6 s^{2} 4 f^{9}$
```


2285. Chapter 3 -
51. The charge on the ion.
52. (a)

(b)

(c)

(d)

(e)


2285. Chapter 3 -
53. Zr
54. $\mathrm{Rb}^{+}, \mathrm{Se}^{2-}$
55. Although both (b) and (c) are correct, (e) encompasses both and is the best answer.
56. K
57. $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{2} 3 d^{10} 4 p^{6} 5 s^{2} 4 d^{10} 5 p^{6} 6 s^{2} 4 f^{14} 5 d^{10}$
58. Co has 27 protons, 27 electrons, and 33 neutrons: $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{2} 3 d^{7}$. I has 53 protons, 53 electrons, and 78 neutrons: $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6} 4 d^{10} 5 s^{2} 5 p^{5}$.
59. Cl
60. O
61. $\mathrm{Rb}<\mathrm{Li}<\mathrm{N}<\mathrm{F}$
62. 15 ( 5 A )
63. $\mathrm{Mg}<\mathrm{Ca}<\mathrm{Rb}<\mathrm{Cs}$
64. $\mathrm{Si}^{++}<\mathrm{Al}^{3+}<\mathrm{Ca}^{2+}<\mathrm{K}^{+}$
65. $\mathrm{Se}, \mathrm{As}^{-}$
66. $\mathrm{Mg}^{2+}<\mathrm{K}^{+}<\mathrm{Br}^{-}<\mathrm{As}^{3-}$
67. $\mathrm{O}, \mathrm{IE}_{1}$
68. Ra
69. (a) metal, inner transition metal; (b) nonmetal, representative element; (c) metal, representative element;


2285. Chapter 3 -
67. $\mathrm{O}, \mathrm{IE}_{1}$
68. Ra
69. (a) metal, inner transition metal; (b) nonmetal, representative element; (c) metal, representative element;
(d) nonmetal, representative element; (e) metal, transition metal; (f) metal, inner transition metal; (g) metal, transition metal; (h) nonmetal, representative element; (i) nonmetal, representative element; (j) metal, representative element
70. (a) He ; (b) Be ; (c) Li; (d) O
71. (a) krypton, Kr ; (b) calcium, Ca ; (c) fluorine, F ; (d) tellurium, Te
72. (a) ${ }_{11}^{23} \mathrm{Na}$; (b) ${ }_{54}^{129} \mathrm{Xe}$; (c) ${ }_{33}^{73} \mathrm{As}$; (d) ${ }_{88}^{226} \mathrm{Ra}$
73. Ionic: $\mathrm{KCl}, \mathrm{MgCl}_{2}$; Covalent: $\mathrm{NCl}_{3}, \mathrm{ICl}, \mathrm{PCl}_{5}, \mathrm{CCl}_{4}$
74. (a) covalent; (b) ionic, $\mathrm{Ba}^{2+}, \mathrm{O}^{2-}$; (c) ionic, $\mathrm{NH}_{4}{ }^{+}, \mathrm{CO}_{3}{ }^{2-}$; (d) ionic, $\mathrm{Sr}^{2+}, \mathrm{H}_{2} \mathrm{PO}_{4}{ }^{-}$; (e) covalent; (f) ionic, $\mathrm{Na}^{+}, \mathrm{O}^{2-}$


2285. Chapter 3 -
75. (a) CaS ; (b) $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}$; (c) $\mathrm{AlBr}_{3}$; (d) $\mathrm{Na}_{2} \mathrm{HPO}_{4}$; (e) $\mathrm{Mg}_{3}\left(\mathrm{PO}_{4}\right)_{2}$


2286. Chapter 4 -
1. The protons in the nucleus do not change during normal chemical reactions. Only the outer electrons move. Positive charges form when electrons are lost.
2. $\mathrm{P}, \mathrm{I}, \mathrm{Cl}$, and O would form anions because they are nonmetals. Mg , $\mathrm{In}, \mathrm{Cs}, \mathrm{Pb}$, and Co would form cations because they are metals.
3. (a) $\mathrm{P}^{3-}$; (b) $\mathrm{Mg}^{2+}$; (c) $\mathrm{Al}^{3+}$; (d) $\mathrm{O}^{2-}$; (e) $\mathrm{Cl}^{-}$; (f) $\mathrm{Cs}^{+}$
4. (a) $[\mathrm{Ar}] 4 s^{2} 3 d^{10} 4 p^{6}$; (b) $[\mathrm{Kr}] 4 d^{10} 5 s^{2} 5 p^{6}$ (c) $1 s^{2}$ (d) $[\mathrm{Kr}] 4 d^{10}$; (e) $[\mathrm{He}] 2 s^{2} 2 p^{6}$; (f) $[\mathrm{Ar}] 3 d^{10}$; (g) $1 s^{2}$ (h) $[\mathrm{He}] 2 s^{2} 2 p^{6}$ (i) $[\mathrm{Kr}] 4 d^{10} 5 s^{2}(\mathrm{j})[\mathrm{Ar}] 3 d^{7}(\mathrm{k})[\mathrm{Ar}] 3 d^{6}$, (l) $[\mathrm{Ar}] 3 d^{10} 4 s^{2}$


2286. Chapter 4 -
5. (a) $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{1}$; $\mathrm{Al}^{3+}$ : $1 s^{2} 2 s^{2} 2 p^{6}$; (b) $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{5}$; $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6}$; (c) $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6} 5 s^{2}$; $\mathrm{Sr}^{2+}: 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6}$; (d) $1 s^{2} 2 s^{1}$; $\mathrm{Li}^{+}: 1 s^{2}$; (e) $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{3} ; 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6}$; (f) $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{4} ; 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6}$


2286. Chapter 4 -
6. NaCl consists of discrete ions arranged in a crystal lattice, not covalently bonded molecules.
7. ionic: (b), (d), (e), (g), and (i); covalent: (a), (c), (f), (h), (j), and (k)
8. (a) Cl; (b) O; (c) O; (d) S; (e) N; (f) P; (g) N
9. (a) H, C, N, O, F; (b) H, I, Br, Cl, F; (c) H, P, S, O, F; (d) Na, Al, H, P, O; (e) Ba, H, As, N, O
10. $\mathrm{N}, \mathrm{O}, \mathrm{F}$, and Cl
11. (a) HF; (b) CO; (c) OH ; (d) PCl ; (e) NH ; (f) PO ; (g) CN
12. (a) cesium chloride; (b) barium oxide; (c) potassium sulfide; (d) beryllium chloride; (e) hydrogen bromide;
(f) aluminum fluoride
13. (a) RbBr ; (b) MgSe ; (c) $\mathrm{Na}_{2} \mathrm{O}$; (d) $\mathrm{CaCl}_{2}$; (e) HF ; (f) GaP ; (g) $\mathrm{AlBr}_{3}$; (h) $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}$
14. (a) $\mathrm{ClO}_{2}$; (b) $\mathrm{N}_{2} \mathrm{O}_{4}$; (c) $\mathrm{K}_{3} \mathrm{P}$; (d) $\mathrm{Ag}_{2} \mathrm{~S}$; (e) $\mathrm{AIF}_{3} \cdot 3 \mathrm{H}_{2} \mathrm{O}$; (f) $\mathrm{SiO}_{2}$


2286. Chapter 4 -
15. (a) chromium(III) oxide; (b) iron(II) chloride; (c) chromium(VI) oxide; (d) titanium(IV) chloride; (e) cobalt(II) chloride hexahydrate; (f) molybdenum(IV) sulfide
16. (a) $\mathrm{K}_{3} \mathrm{PO}_{4}$; (b) $\mathrm{CuSO}_{4}$; (c) $\mathrm{CaCl}_{2}$; (d) $\mathrm{TiO}_{2}$; (e) $\mathrm{NH}_{4} \mathrm{NO}_{3}$; (f) $\mathrm{NaHSO}_{4}$
17. (a) manganese(IV) oxide; (b) mercury(I) chloride; (c) iron(III) nitrate; (d) titanium(IV) chloride; (e) copper(II) bromide
18. (a) eight electrons:


2286. Chapter 4 -
$$
: \ddot{A s}:^{3-}
$$

(b) eight electrons:

$$
: \ddot{:}
$$

(c) no electrons $\mathrm{Be}^{2+}$
(d) eight electrons:

(e) no electrons $\mathrm{Ga}^{3+}$
(f) no electrons $\mathrm{Li}^{+}$
(g) eight electrons:

$: \ddot{N}:$
36. (a)

$$
\mathrm{Mg}^{2+} \quad: \ddot{\mathrm{S}} \mathbf{:}^{2-}
$$

(b)

$$
\mathrm{Al}^{3+} \quad \because \ddot{\mathrm{O}}{ }^{2-}
$$

(c)

$$
\mathrm{Ga}^{3+} \quad: \ddot{\mathrm{c}} \overline{:} \bar{\square}
$$

(d)

$$
\mathrm{K}^{+} \quad \ddot{\ddot{\mathrm{O}}^{2-}}
$$

(e)

$$
\mathrm{Li}^{+} \quad: \ddot{\mathrm{N}}^{3-}
$$

(f)

$$
\mathrm{K}^{+} \quad: \ddot{\mathrm{F}} \bar{\square}
$$

38.

: $\mathrm{P} \equiv \mathrm{P}$ :
40. (a)
$: \ddot{o}=\ddot{0}:$

In this case, the Lewis structure is inadequate to depict the fact that experimental studies have shown two unpaired electrons in each oxygen molecule.
(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)
$\mathrm{H}-\mathrm{C} \equiv \mathrm{C}-\mathrm{H}$
(j)
$: \ddot{\mathrm{Cl}}-\mathrm{C} \equiv \mathrm{N}:$
(k)
$C \equiv C^{2+}$
42. (a) $\mathrm{SeF}_{6}$ :

(b) $\mathrm{XeF}_{4}$ :

(c) $\mathrm{SeCl}_{3}{ }^{+}$:


2286. Chapter 4 -
(b) $\mathrm{XeF}_{4}$ :

(c) $\mathrm{SeCl}_{3}{ }^{+}$:

(d) $\mathrm{Cl}_{2} \mathrm{BBCl}_{2}$ :

44. Two valence electrons per Pb atom are transferred to Cl atoms; the resulting $\mathrm{Pb}^{2+}$ ion has a $6 s^{2}$ valence shell configuration. Two of the valence electrons in the HCl molecule are shared, and the other six are located on the Cl atom as lone pairs of electrons.
46.

48.

50. (a)

(b)

(c)

(d)

(e)

52.

54. Each bond includes a sharing of electrons between atoms. Two electrons are shared in a single bond; four electrons are shared in a double bond; and six electrons are shared in a triple bond.
56. (a)

(b)

(c)

(d)

(e)

58.

60. (a)

$$
\ddot{O}=c=\ddot{o}
$$

(b)

$$
: C \equiv O:
$$

CO has the strongest carbon-oxygen bond because there is a triple bond joining C and $\mathrm{O} . \mathrm{CO}_{2}$ has double bonds.
62. (a) H: $0, \mathrm{Cl}: 0$; (b) $\mathrm{C}: 0, \mathrm{~F}: 0$; (c) $\mathrm{P}: 0, \mathrm{Cl} 0$; (d) $\mathrm{P}: 0, \mathrm{~F}: 0$
64. Cl in $\mathrm{Cl}_{2}: 0 ; \mathrm{Cl}$ in $\mathrm{BeCl}_{2}: 0 ; \mathrm{Cl}$ in $\mathrm{ClF}_{5}: 0$
66. (a)

(b)

(c)

(d)

68. HOCl
70. The structure that gives zero formal charges is consistent with the actual structure:

72. $\mathrm{NF}_{3}$;

74.


2286. Chapter 4 -
75. The placement of the two sets of unpaired electrons in water forces the bonds to assume a tetrahedral arrangement, and the resulting HOH molecule is bent. The HBeH molecule (in which Be has only two electrons to bond with the two electrons from the hydrogens) must have the electron pairs as far from one another as possible and is therefore linear.
77. Space must be provided for each pair of electrons whether they are in a bond or are present as lone pairs. Electron-pair geometry considers the placement of all electrons. Molecular structure considers only the bonding-pair geometry.
79. As long as the polar bonds are compensated (for example. two identical atoms are found directly across the central atom from one another), the molecule can be nonpolar.
81. (a) Both the electron geometry and the molecular structure are octahedral. (b) Both the electron geometry and the molecular structure are trigonal bipyramid. (c) Both the electron geometry and the molecular structure are linear. (d) Both the electron geometry and the molecular structure are trigonal planar.
83. (a) electron-pair geometry: octahedral, molecular structure: square pyramidal; (b) electron-pair geometry: tetrahedral, molecular structure: bent; (c) electron-pair geometry: octahedral, molecular structure: square planar; (d) electron-pair geometry: tetrahedral, molecular structure: trigonal pyramidal; (e) electron-pair geometry: trigonal bypyramidal, molecular structure: seesaw; (f) electron-pair geometry: tetrahedral, molecular structure: bent (109 ${ }^{\circ}$ )
85. (a) electron-pair geometry: trigonal planar, molecular structure: bent ( $120^{\circ}$ ); (b) electron-pair geometry: linear, molecular structure: linear; (c) electron-pair geometry: trigonal planar, molecular structure: trigonal planar; (d) electron-pair geometry: tetrahedral, molecular structure: trigonal pyramidal; (e) electron-pair geometry: tetrahedral, molecular structure: tetrahedral; (f) electron-pair geometry: trigonal bipyramidal, molecular structure: seesaw; (g) electron-pair geometry: tetrahedral, molecular structure: trigonal pyramidal


2286. Chapter 4 -
87. All of these molecules and ions contain polar bonds. Only $\mathrm{ClF}_{5}, \mathrm{ClO}_{2}{ }^{-}, \mathrm{PCl}_{3}, \mathrm{SeF}_{4}$, and $\mathrm{PH}_{2}{ }^{-}$have dipole moments.
89. $\mathrm{SeS}_{2}, \mathrm{CCl}_{2} \mathrm{~F}_{2}, \mathrm{PCl}_{3}$, and ClNO all have dipole moments.
91. $P$
93. nonpolar
95. (a) tetrahedral; (b) trigonal pyramidal; (c) bent (109$) ; ~(d) ~ t r i g o n a l ~ p l a n a r ; ~(e) ~ b e n t ~(109 ㅇ) ; ~(f) ~ b e n t ~(109 ㅇ) ; ~$
(g) $\mathrm{CH}_{3} \mathrm{CCH}$ tetrahedral, $\mathrm{CH}_{3} \mathrm{CCH}$ linear; (h) tetrahedral; (i) $\mathrm{H}_{2} \mathrm{CCCH}_{2}$ linear; $\mathrm{H}_{2} \mathrm{CCCH}_{2}$ trigonal planar
97.
$B-A$ - $\quad$ CO $_{2}$, linear
$B-\dot{A} \_{B}^{\bullet} \mathrm{H}_{2} \mathrm{O}$, bent with an approximately $109^{\circ}$ angle
$B-\ddot{A} \mathrm{SO}_{2}$, bent with an approximately $120^{\circ}$ angle
99. (a)


2286. Chapter 4 -
(b)

```
#}=c=\ddot{S
```

(c)


2287. : $\mathrm{C} \equiv \mathrm{s}$ : -
(d) $\mathrm{CS}_{3}{ }^{2-}$ includes three regions of electron density (all are bonds with no lone pairs); the shape is trigonal planar; $\mathrm{CS}_{2}$ has only two regions of electron density (all bonds with no lone pairs); the shape is linear
101. The Lewis structure is made from three units, but the atoms must be rearranged:

103. The molecular dipole points away from the hydrogen atoms.
105. The structures are very similar. In the model mode, each electron group occupies the same amount of space, so the bond angle is shown as $109.5^{\circ}$. In the "real" mode, the lone pairs are larger, causing the hydrogens to be compressed. This leads to the smaller angle of $104.5^{\circ}$.


2288. Chapter 5 -
1. Similarities: Both types of bonds result from overlap of atomic orbitals on adjacent atoms and contain a maximum of two electrons. Differences: $\sigma$ bonds are stronger and result from end-to-end overlap and all single bonds are $\sigma$ bonds; $\pi$ bonds between the same two atoms are weaker because they result from side-by-side overlap, and multiple bonds contain one or more $\pi$ bonds (in addition to a $\sigma$ bond).
2. Bonding: One $\sigma$ bond and one $\pi$ bond. The $s$ orbitals are filled and do not overlap. The $p$ orbitals overlap along the axis to form a $\sigma$ bond and side-by-side to form the $\pi$ bond.

3. No, two of the $p$ orbitals (one on each N ) will be oriented end-to-end and will form a $\sigma$ bond.

4. Hybridization is introduced to explain the geometry of bonding orbitals in valance bond theory.
5. There are no $d$ orbitals in the valence shell of carbon.
6. trigonal planar, $s p^{2}$; trigonal pyramidal (one lone pair on A ) $s p^{3}$; T -shaped (two lone pairs on $\mathrm{A} s p^{3} d$, or (three lone pairs on A) $s p^{3} d^{2}$
7. (a) Each $S$ has a bent $\left(109^{\circ}\right)$ geometry, $s p^{3}$

(b) Bent ( $120^{\circ}$ ), $s p^{2}$

(c) Trigonal planar, $s p^{2}$

(d) Tetrahedral, $s p^{3}$

8. (a) $\mathrm{XeF}_{2}$
(b)

(c) linear (d) $s p^{3} d$
9. (a)


2288. Chapter 5 -
8. (a) $\mathrm{XeF}_{2}$
(b)

(c) linear (d) $s p^{3} d$
9. (a)

(b) P atoms, trigonal pyramidal; S atoms, bent, with two lone pairs; Cl atoms, trigonal pyramidal; (c) Hybridization about $\mathrm{P}, \mathrm{S}$, and Cl is, in all cases, $s p^{3}$; (d) Oxidation states $\mathrm{P}+1, \mathrm{~S}-1 \frac{1}{3}, \mathrm{Cl}+5, \mathrm{O}-2$. Formal charges: P 0; S 0; Cl +2: O-1
10.

Phosphorus and nitrogen can form $s p^{3}$ hybrids to form three bonds and hold one lone pair in $\mathrm{PF}_{3}$ and $\mathrm{NF}_{3}$, respectively. However, nitrogen has no valence $d$ orbitals, so it cannot form a set of $s p^{3} d$ hybrid orbitals to bind five fluorine atoms in $\mathrm{NF}_{5}$. Phosphorus has $d$ orbitals and can bind five fluorine atoms with $s p^{3} d$ hybrid orbitals in $\mathrm{PF}_{5}$.
21. A triple bond consists of one $\sigma$ bond and two $\pi$ bonds. A $\sigma$ bond is stronger than a $\pi$ bond due to greater overlap.
23. (a)


2288. Chapter 5 -
(b) The terminal carbon atom uses $s p^{3}$ hybrid orbitals, while the central carbon atom is $s p$ hybridized. (c) Each of the two $\pi$ bonds is formed by overlap of a $2 p$ orbital on carbon and a nitrogen $2 p$ orbital.
25. (a) $s p^{2}$; (b) $s p$; (c) $s p^{2}$; (d) $s p^{3}$; (e) $s p^{3}$; (f) $s p^{3} d$; (g) $s p^{3}$
27. (a) $s p^{2}$, delocalized; (b) $s p$, localized; (c) $s p^{2}$, delocalized; (d) $s p^{3}$, delocalized
29.

Orbitals in an isolated $C$ atom

Orbitals in the $s p$ hybridized C in $\mathrm{CO}_{2}$


2288. Chapter 5 -
Each of the four electrons is in a separate orbital and overlaps with an electron on an oxygen atom.
31. (a) Similarities: Both are bonding orbitals that can contain a maximum of two electrons. Differences: $\sigma$
orbitals are end-to-end combinations of atomic orbitals, whereas $\pi$ orbitals are formed by side-by-side overlap of orbitals. (b) Similarities: Both are quantum-mechanical constructs that represent the probability of finding the electron about the atom or the molecule. Differences: $\psi$ for an atomic orbital describes the behavior of only one electron at a time based on the atom. For a molecule, $\psi$ represents a mathematical combination of atomic orbitals. (c) Similarities: Both are orbitals that can contain two electrons. Differences: Bonding orbitals result in holding two or more atoms together. Antibonding orbitals have the effect of destabilizing any bonding that has occurred.
33. An odd number of electrons can never be paired, regardless of the arrangement of the molecular orbitals. It will always be paramagnetic.
35. Bonding orbitals have electron density in close proximity to more than one nucleus. The interaction between the bonding positively charged nuclei and negatively charged electrons stabilizes the system.
37. The pairing of the two bonding electrons lowers the energy of the system relative to the energy of the nonbonded electrons.


2288. Chapter 5 -
37. The pairing of the two bonding electrons lowers the energy of the system relative to the energy of the nonbonded electrons.
39. (a) $\mathrm{H}_{2}$ bond order $=1, \mathrm{H}_{2}{ }^{+}$bond order $=0.5, \mathrm{H}_{2}{ }^{-}$bond order $=0.5$, strongest bond is $\mathrm{H}_{2}$; (b) $\mathrm{O}_{2}$ bond order $=2, \mathrm{O}_{2}{ }^{2+}$ bond order $=3 ; \mathrm{O}_{2}{ }^{2-}$ bond order $=1$, strongest bond is $\mathrm{O}_{2}{ }^{2+}$; (c) $\mathrm{Li}_{2}$ bond order $=1, \mathrm{Be}_{2}{ }^{+}$ bond order $=0.5, \mathrm{Be}_{2}$ bond order $=0$, strongest bond is $\mathrm{Li}_{2}$; (d) $\mathrm{F}_{2}$ bond order $=1, \mathrm{~F}_{2}{ }^{+}$bond order $=1.5$, $\mathrm{F}_{2}{ }^{-}$bond order $=0.5$, strongest bond is $\mathrm{F}_{2}{ }^{+}$; (e) $\mathrm{N}_{2}$ bond order $=3, \mathrm{~N}_{2}{ }^{+}$bond order $=2.5, \mathrm{~N}_{2}{ }^{-}$bond order $=2.5$, strongest bond is $\mathrm{N}_{2}$
41. (a) $\mathrm{H}_{2}$; (b) $\mathrm{N}_{2}$; (c) O ; (d) $\mathrm{C}_{2}$; (e) $\mathrm{B}_{2}$
43. Yes, fluorine is a smaller atom than Li, so atoms in the $2 s$ orbital are closer to the nucleus and more stable.
45. $2+$


2288. Chapter 5 -
43. Yes, fluorine is a smaller atom than Li, so atoms in the $2 s$ orbital are closer to the nucleus and more stable.
45. $2+$
47. $\mathrm{N}_{2}$ has s-p mixing, so the $\pi$ orbitals are the last filled in $\mathrm{N}_{2}{ }^{2+} . \mathrm{O}_{2}$ does not have s-p mixing, so the $\sigma_{p}$ orbital fills before the $\pi$ orbitals.


2289. Chapter 6 -
1. (a) 12.01 amu ; (b) 12.01 amu ; (c) 144.12 amu ; (d) 60.05 amu
2. (a) 123.896 amu ; (b) 18.015 amu ; (c) 164.086 amu ; (d) 60.052 amu ; (e) 342.297 amu
3. (a) 56.107 amu ;
(b) 54.091 amu ;
(c) 199.9976 amu ;
(d) 97.9950 amu
4. (a) $\% \mathrm{~N}=82.24 \%$
\% H = 17.76\%;
(b) $\% \mathrm{Na}=29.08 \%$
\% $\mathrm{S}=40.56 \%$
\% O = 30.36\%;
(c) $\% \mathrm{Ca}^{2+}=38.76 \%$
5. $\% \mathrm{NH}_{3}=38.2 \%$
6. (a) $\mathrm{CS}_{2}$
(b) $\mathrm{CH}_{2} \mathrm{O}$
7. $\mathrm{C}_{6} \mathrm{H}_{6}$
8. $\mathrm{Mg}_{3} \mathrm{Si}_{2} \mathrm{H}_{3} \mathrm{O}_{8}$ (empirical formula), $\mathrm{Mg}_{6} \mathrm{Si}_{4} \mathrm{H}_{6} \mathrm{O}_{16}$ (molecular formula)
9. $\mathrm{C}_{15} \mathrm{H}_{15} \mathrm{~N}_{3}$
10. We need to know the number of moles of sulfuric acid dissolved in the solution and the volume of the solution.
11. (a) 0.679 M ; (b) 1.00 M ; (c) 0.06998 M ; (d) 1.75 M ; (e) 0.070 M ; (f) 6.6 M


2289. Chapter 6 -
12. (a) determine the number of moles of glucose in 0.500 L of solution; determine the molar mass of glucose; determine the mass of glucose from the number of moles and its molar mass; (b) 27 g
13. (a) $37.0 \mathrm{~mol} \mathrm{H}_{2} \mathrm{SO}_{4}, 3.63 \times 10^{3} \mathrm{~g} \mathrm{H}_{2} \mathrm{SO}_{4}$; (b) $3.8 \times 10^{-7} \mathrm{~mol} \mathrm{NaCN}, 1.9 \times 10^{-5} \mathrm{~g} \mathrm{NaCN}$; (c) $73.2 \mathrm{~mol} \mathrm{H} \mathrm{H}_{2} \mathrm{CO}$, $2.20 \mathrm{~kg} \mathrm{H}_{2} \mathrm{CO}$; (d) $5.9 \times 10^{-7} \mathrm{~mol} \mathrm{FeSO}_{4}, 8.9 \times 10^{-5} \mathrm{~g} \mathrm{FeSO}_{4}$
14. (a) Determine the molar mass of $\mathrm{KMnO}_{4}$; determine the number of moles of $\mathrm{KMnO}_{4}$ in the solution; from the number of moles and the volume of solution, determine the molarity; (b) $1.15 \times 10^{-3} \mathrm{M}$
15. (a) $5.04 \times 10^{-3} \mathrm{M}$; (b) 0.499 M ; (c) 9.92 M ; (d) $1.1 \times 10^{-3} \mathrm{M}$
16. $0.025 M$
17. 0.5000 L
18. 1.9 mL
19. (a) $0.125 M$; (b) $0.04888 M$; (c) $0.206 M$; (d) $0.0056 M$
20. 11.9 M
21. 1.6 L


2289. Chapter 6 -
20. 11.9 M
21. 1.6 L
22. (a) The dilution equation can be used, appropriately modified to accommodate mass-based concentration units: $\%$ mass $_{1} \times$ mass $_{1}=\%$ mass $_{2} \times$ mass $_{2}$. This equation can be rearranged to isolate mass ${ }_{1}$ and the given quantities substituted into this equation. (b) 58.8 g
23. 114 g
24. $1.75 \times 10^{-3} \mathrm{M}$
25. $95 \mathrm{mg} / \mathrm{dL}$
26. $2.38 \times 10^{-4} \mathrm{~mol}$
27. 0.29 mol


2290. Chapter 7 -
1. An equation is balanced when the same number of each element is represented on the reactant and product sides. Equations must be balanced to accurately reflect the law of conservation of matter.
2. (a) $\mathrm{PCl}_{5}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{POCl}_{3}(l)+2 \mathrm{HCl}(a q)$; (b)
$3 \mathrm{Cu}(s)+8 \mathrm{HNO}_{3}(a q) \longrightarrow 3 \mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}(a q)+4 \mathrm{H}_{2} \mathrm{O}(l)+2 \mathrm{NO}(g) ;(\mathrm{c}) \mathrm{H}_{2}(g)+\mathrm{I}_{2}(s) \longrightarrow 2 \mathrm{HI}(s) ;(\mathrm{d})$
$4 \mathrm{Fe}(s)+3 \mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{Fe}_{2} \mathrm{O}_{3}(s)$; (e) $2 \mathrm{Na}(s)+2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2 \mathrm{NaOH}(a q)+\mathrm{H}_{2}(g)$; (f)
$\left(\mathrm{NH}_{4}\right)_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}(s) \longrightarrow \mathrm{Cr}_{2} \mathrm{O}_{3}(s)+\mathrm{N}_{2}(g)+4 \mathrm{H}_{2} \mathrm{O}(g) ;(\mathrm{g}) \mathrm{P}_{4}(s)+6 \mathrm{Cl}_{2}(g) \longrightarrow 4 \mathrm{PCl}_{3}(l) ;(\mathrm{h})$
$\mathrm{PtCl}_{4}(s) \longrightarrow \mathrm{Pt}(s)+2 \mathrm{Cl}_{2}(g)$


2290. Chapter 7 -
$\mathrm{PtCl}_{4}(s) \longrightarrow \mathrm{Pt}(s)+2 \mathrm{Cl}_{2}(g)$
3. (a) $\mathrm{CaCO}_{3}(s) \longrightarrow \mathrm{CaO}(s)+\mathrm{CO}_{2}(g)$; (b) $2 \mathrm{C}_{4} \mathrm{H}_{10}(g)+13 \mathrm{O}_{2}(g) \longrightarrow 8 \mathrm{CO}_{2}(g)+10 \mathrm{H}_{2} \mathrm{O}(g)$; (c)
$\mathrm{MgCl}_{2}(a q)+2 \mathrm{NaOH}(a q) \longrightarrow \mathrm{Mg}(\mathrm{OH})_{2}(s)+2 \mathrm{NaCl}(a q) ;(\mathrm{d}) 2 \mathrm{H}_{2} \mathrm{O}(g)+2 \mathrm{Na}(s) \longrightarrow 2 \mathrm{NaOH}(s)+\mathrm{H}_{2}(g)$
4. (a) $\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}, \mathrm{KClO}_{3}$; (b) $2 \mathrm{KClO}_{3}(s) \longrightarrow 2 \mathrm{KCl}(s)+3 \mathrm{O}_{2}(g)$; (c)
$2 \mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}(s) \longrightarrow 2 \mathrm{BaO}(s)+2 \mathrm{~N}_{2}(g)+5 \mathrm{O}_{2}(g)$; (d) $2 \mathrm{Mg}(s)+\mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{MgO}(s) ;$
$4 \mathrm{Al}(s)+3 \mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{Al}_{2} \mathrm{O}_{3}(s) ; 4 \mathrm{Fe}(s)+3 \mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{Fe}_{2} \mathrm{O}_{3}(s)$


2290. Chapter 7 -
5. (a) $4 \mathrm{HF}(a q)+\mathrm{SiO}_{2}(s) \longrightarrow \mathrm{SiF}_{4}(g)+2 \mathrm{H}_{2} \mathrm{O}(l)$; (b) complete ionic equation:
$2 \mathrm{Na}^{+}(a q)+2 \mathrm{~F}^{-}(a q)+\mathrm{Ca}^{2+}(a q)+2 \mathrm{Cl}^{-}(a q) \longrightarrow \mathrm{CaF}_{2}(s)+2 \mathrm{Na}^{+}(a q)+2 \mathrm{Cl}^{-}(a q)$, net ionic equation: $2 \mathrm{~F}^{-}(a q)+\mathrm{Ca}^{2+}(a q) \longrightarrow \mathrm{CaF}_{2}(s)$
6. (a)
$2 \mathrm{~K}^{+}(a q)+\mathrm{C}_{2} \mathrm{O}_{4}{ }^{2-}(a q)+\mathrm{Ba}^{2+}(a q)+2 \mathrm{OH}^{-}(a q) \longrightarrow 2 \mathrm{~K}^{+}(a q)+2 \mathrm{OH}^{-}(a q)+\mathrm{BaC}_{2} \mathrm{O}_{4}(s) \quad$ (complete)
$\mathrm{Ba}^{2+}(a q)+\mathrm{C}_{2} \mathrm{O}_{4}{ }^{2-}(a q) \longrightarrow \mathrm{BaC}_{2} \mathrm{O}_{4}(s) \quad$ (net)
(b)
$\mathrm{Pb}^{2+}(a q)+2 \mathrm{NO}_{3}{ }^{-}(a q)+2 \mathrm{H}^{+}(a q)+\mathrm{SO}_{4}{ }^{2-}(a q) \longrightarrow \mathrm{PbSO}_{4}(s)+2 \mathrm{H}^{+}(a q)+2 \mathrm{NO}_{3}{ }^{-}(a q) \quad$ (complete)


2290. Chapter 7 -
$\mathrm{Pb}^{2+}(a q)+\mathrm{SO}_{4}{ }^{2-}(a q) \longrightarrow \mathrm{PbSO}_{4}(s) \quad$ (net)
(c) $\mathrm{CaCO}_{3}(s)+2 \mathrm{H}^{+}(a q)+\mathrm{SO}_{4}{ }^{2-}(a q) \longrightarrow \mathrm{CaSO}_{4}(s)+\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l) \quad$ (complete)
$\mathrm{CaCO}_{3}(s)+2 \mathrm{H}^{+}(a q)+\mathrm{SO}_{4}{ }^{2-}(a q) \longrightarrow \mathrm{CaSO}_{4}(s)+\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l) \quad$ (net)
7. (a) oxidation-reduction (addition); (b) acid-base (neutralization); (c) oxidation-reduction (combustion)
8. It is an oxidation-reduction reaction because the oxidation state of the silver changes during the reaction.
9. (a) $\mathrm{H}+1, \mathrm{P}+5, \mathrm{O}-2$; (b) $\mathrm{Al}+3, \mathrm{H}+1, \mathrm{O}-2$; (c) $\mathrm{Se}+4, \mathrm{O}-2$; (d) $\mathrm{K}+1, \mathrm{~N}+3, \mathrm{O}-2$; (e) In $+3, \mathrm{~S}-2$; (f) $\mathrm{P}+3, \mathrm{O}-2$
10. (a) acid-base; (b) oxidation-reduction: Na is oxidized, $\mathrm{H}^{+}$is reduced; (c) oxidation-reduction: Mg is oxidized, $\mathrm{Cl}_{2}$ is reduced; (d) acid-base; (e) oxidation-reduction: $\mathrm{P}^{3-}$ is oxidized, $\mathrm{O}_{2}$ is reduced; (f) acid-base


2290. Chapter 7 -
11. (a) $2 \mathrm{HCl}(g)+\mathrm{Ca}(\mathrm{OH})_{2}(s) \longrightarrow \mathrm{CaCl}_{2}(s)+2 \mathrm{H}_{2} \mathrm{O}(l)$; (b)
$\mathrm{Sr}(\mathrm{OH})_{2}(a q)+2 \mathrm{HNO}_{3}(a q) \longrightarrow \mathrm{Sr}\left(\mathrm{NO}_{3}\right)_{2}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l)$
12. (a) $2 \mathrm{Al}(s)+3 \mathrm{~F}_{2}(g) \longrightarrow 2 \mathrm{AlF}_{3}(s)$; (b) $2 \mathrm{Al}(s)+3 \mathrm{CuBr}_{2}(a q) \longrightarrow 3 \mathrm{Cu}(s)+2 \mathrm{AlBr}_{3}(a q)$; (c)
$\mathrm{P}_{4}(s)+5 \mathrm{O}_{2}(g) \longrightarrow \mathrm{P}_{4} \mathrm{O}_{10}(s) ;(\mathrm{d}) \mathrm{Ca}(s)+2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{Ca}(\mathrm{OH})_{2}(a q)+\mathrm{H}_{2}(g)$
13. (a) $\mathrm{Mg}(\mathrm{OH})_{2}(s)+2 \mathrm{HClO}_{4}(a q) \longrightarrow \mathrm{Mg}^{2+}(a q)+2 \mathrm{ClO}_{4}{ }^{-}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l)$; (b)
$\mathrm{SO}_{3}(g)+2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{H}_{3} \mathrm{O}^{+}(a q)+\mathrm{HSO}_{4}{ }^{-}(a q)$, (a solution of $\mathrm{H}_{2} \mathrm{SO}_{4}$ ); (c)


2290. Chapter 7 -
$\mathrm{SrO}(s)+\mathrm{H}_{2} \mathrm{SO}_{4}(l) \longrightarrow \mathrm{SrSO}_{4}(s)+\mathrm{H}_{2} \mathrm{O}$
14. $\mathrm{H}_{2}(g)+\mathrm{F}_{2}(g) \longrightarrow 2 \mathrm{HF}(g)$
15. $2 \mathrm{NaBr}(a q)+\mathrm{Cl}_{2}(g) \longrightarrow 2 \mathrm{NaCl}(a q)+\mathrm{Br}_{2}(l)$
16. $2 \mathrm{LiOH}(a q)+\mathrm{CO}_{2}(g) \longrightarrow \mathrm{Li}_{2} \mathrm{CO}_{3}(a q)+\mathrm{H}_{2} \mathrm{O}(l)$
17. (a) $\mathrm{Ca}(\mathrm{OH})_{2}(s)+\mathrm{H}_{2} \mathrm{~S}(g) \longrightarrow \mathrm{CaS}(s)+2 \mathrm{H}_{2} \mathrm{O}(l)$; (b)
$\mathrm{Na}_{2} \mathrm{CO}_{3}(a q)+\mathrm{H}_{2} \mathrm{~S}(g) \longrightarrow \mathrm{Na}_{2} \mathrm{~S}(a q)+\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l)$
18. (a) step 1: $\mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g) \longrightarrow 2 \mathrm{NH}_{3}(g)$, step 2 :
$\mathrm{NH}_{3}(g)+\mathrm{HNO}_{3}(a q) \longrightarrow \mathrm{NH}_{4} \mathrm{NO}_{3}(a q) \longrightarrow \mathrm{NH}_{4} \mathrm{NO}_{3}(s)$ (after drying); (b)
$\mathrm{H}_{2}(g)+\mathrm{Br}_{2}(l) \longrightarrow 2 \mathrm{HBr}(g)$; (c) $\mathrm{Zn}(s)+\mathrm{S}(s) \longrightarrow \mathrm{ZnS}(s)$ and


2290. Chapter 7 -
$\mathrm{ZnS}(s)+2 \mathrm{HCl}(a q) \longrightarrow \mathrm{ZnCl}_{2}(a q)+\mathrm{H}_{2} \mathrm{~S}(g)$
19. (a) $\mathrm{Sn}^{4+}(a q)+2 \mathrm{e}^{-} \longrightarrow \mathrm{Sn}^{2+}(a q)$, (b) $\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}\right]^{+}(a q)+\mathrm{e}^{-} \longrightarrow \mathrm{Ag}(s)+2 \mathrm{NH}_{3}(a q)$; (c)
$\mathrm{Hg}_{2} \mathrm{Cl}_{2}(s)+2 \mathrm{e}^{-} \longrightarrow 2 \mathrm{Hg}(l)+2 \mathrm{Cl}^{-}(a q) ;(\mathrm{d}) 2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{O}_{2}(g)+4 \mathrm{H}^{+}(a q)+4 \mathrm{e}^{-}$; (e)
$6 \mathrm{H}_{2} \mathrm{O}(l)+2 \mathrm{IO}_{3}^{-}(a q)+10 \mathrm{e}^{-} \longrightarrow \mathrm{I}_{2}(s)+12 \mathrm{OH}^{-}(a q) ;(\mathrm{f})$
$\mathrm{H}_{2} \mathrm{O}(l)+\mathrm{SO}_{3}{ }^{2-}(a q) \longrightarrow \mathrm{SO}_{4}{ }^{2-}(a q)+2 \mathrm{H}^{+}(a q)+2 \mathrm{e}^{-}$; (g)
$8 \mathrm{H}^{+}(a q)+\mathrm{MnO}_{4}^{-}(a q)+5 \mathrm{e}^{-} \longrightarrow \mathrm{Mn}^{2+}(a q)+4 \mathrm{H}_{2} \mathrm{O}(l) ;(\mathrm{h})$


2290. Chapter 7 -
$\mathrm{Cl}^{-}(a q)+6 \mathrm{OH}^{-}(a q) \longrightarrow \mathrm{ClO}_{3}^{-}(a q)+3 \mathrm{H}_{2} \mathrm{O}(l)+6 \mathrm{e}^{-}$
20. (a) $\mathrm{Sn}^{2+}(a q)+2 \mathrm{Cu}^{2+}(a q) \longrightarrow \mathrm{Sn}^{4+}(a q)+2 \mathrm{Cu}^{+}(a q)$; (b)
$\mathrm{H}_{2} \mathrm{~S}(g)+\mathrm{Hg}_{2}{ }^{2+}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2 \mathrm{Hg}(l)+\mathrm{S}(s)+2 \mathrm{H}_{3} \mathrm{O}^{+}(a q) ;$ (c)
$5 \mathrm{CN}^{-}(a q)+2 \mathrm{ClO}_{2}(a q)+3 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 5 \mathrm{CNO}^{-}(a q)+2 \mathrm{Cl}^{-}(a q)+2 \mathrm{H}_{3} \mathrm{O}^{+}(a q) ;$ (d)
$\mathrm{Fe}^{2+}(a q)+\mathrm{Ce}^{4+}(a q) \longrightarrow \mathrm{Fe}^{3+}(a q)+\mathrm{Ce}^{3+}(a q)$; (e)
$2 \mathrm{HBrO}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2 \mathrm{H}_{3} \mathrm{O}^{+}(a q)+2 \mathrm{Br}^{-}(a q)+\mathrm{O}_{2}(g)$


2290. Chapter 7 -
21. (a) $2 \mathrm{MnO}_{4}{ }^{-}(a q)+3 \mathrm{NO}_{2}{ }^{-}(a q)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2 \mathrm{MnO}_{2}(s)+3 \mathrm{NO}_{3}{ }^{-}(a q)+2 \mathrm{OH}^{-}(a q)$; (b)
$3 \mathrm{MnO}_{4}{ }^{2-}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 2 \mathrm{MnO}_{4}^{-}(a q)+4 \mathrm{OH}^{-}(a q)+\mathrm{MnO}_{2}(s)$ (in base); (c)
$\mathrm{Br}_{2}(l)+\mathrm{SO}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow 4 \mathrm{H}^{+}(a q)+2 \mathrm{Br}^{-}(a q)+\mathrm{SO}_{4}{ }^{2-}(a q)$
22. (a) $0.435 \mathrm{~mol} \mathrm{Na}, 0.217 \mathrm{~mol} \mathrm{Cl}_{2}, 15.4 \mathrm{~g} \mathrm{Cl}_{2}$; (b) $0.005780 \mathrm{~mol} \mathrm{HgO}, 2.890 \times 10^{-3} \mathrm{~mol} \mathrm{O}_{2}, 9.248 \times 10^{-2} \mathrm{~g} \mathrm{O}_{2}$;


2290. Chapter 7 -
(c) $8.00 \mathrm{~mol} \mathrm{NaNO}_{3}, 6.8 \times 10^{2} \mathrm{~g} \mathrm{NaNO}_{3}$; (d) $1665 \mathrm{~mol} \mathrm{CO}_{2}, 73.3 \mathrm{~kg} \mathrm{CO}_{2}$; (e) $18.86 \mathrm{~mol} \mathrm{CuO}, 2.330 \mathrm{~kg} \mathrm{CuCO} 3$;
(f) $0.4580 \mathrm{~mol} \mathrm{C}_{2} \mathrm{H}_{4} \mathrm{Br}_{2}, 86.05 \mathrm{~g} \mathrm{C}_{2} \mathrm{H}_{4} \mathrm{Br}_{2}$
23. (a) $0.0686 \mathrm{~mol} \mathrm{Mg}, 1.67 \mathrm{~g} \mathrm{Mg}$; (b) $2.701 \times 10^{-3} \mathrm{~mol} \mathrm{O}_{2}, 0.08644 \mathrm{~g} \mathrm{O}_{2}$; (c) $6.43 \mathrm{~mol} \mathrm{MgCO}_{3}, 542 \mathrm{~g} \mathrm{MgCO}_{3}$ (d) $768 \mathrm{~mol} \mathrm{H}_{2} \mathrm{O}, 13.8 \mathrm{~kg} \mathrm{H}_{2} \mathrm{O}$; (e) $16.31 \mathrm{~mol} \mathrm{BaO}_{2}, 2762 \mathrm{~g} \mathrm{BaO}_{2}$; (f) $0.207 \mathrm{~mol} \mathrm{C}_{2} \mathrm{H}_{4}, 5.81 \mathrm{~g} \mathrm{C}_{2} \mathrm{H}_{4}$


2290. Chapter 7 -
24. (a) volume HCl solution $\longrightarrow \mathrm{mol} \mathrm{HCl} \longrightarrow \mathrm{mol} \mathrm{GaCl}_{3}$; (b) $1.25 \mathrm{~mol} \mathrm{GaCl}_{3}, 2.2 \times 10^{2} \mathrm{~g} \mathrm{GaCl}_{3}$
25. (a) $5.337 \times 10^{22}$ molecules; (b) $10.41 \mathrm{~g} \mathrm{Zn}(\mathrm{CN})_{2}$
26. $\mathrm{SiO}_{2}+3 \mathrm{C} \longrightarrow \mathrm{SiC}+2 \mathrm{CO}, 4.50 \mathrm{~kg} \mathrm{SiO}$
27. $5.00 \times 10^{3} \mathrm{~kg}$
28. $1.28 \times 10^{5} \mathrm{~g} \mathrm{CO}_{2}$
29. 161.4 mL KI solution
30. $176 \mathrm{~g} \mathrm{TiO}_{2}$
31. The limiting reactant is Cl 2 .
32. Percent yield $=31 \%$
33. $\mathrm{g} \mathrm{CCl}_{4} \longrightarrow \mathrm{~mol} \mathrm{CCl}_{4} \longrightarrow \operatorname{mol~CCl}_{2} \mathrm{~F}_{2} \longrightarrow \mathrm{~g} \mathrm{CCl}_{2} \mathrm{~F}_{2}$, percent yield $=48.3 \%$
34. percent yield $=91.3 \%$
35. Convert mass of ethanol to moles of ethanol; relate the moles of ethanol to the moles of ether produced using the stoichiometry of the balanced equation. Convert moles of ether to grams; divide the actual grams of ether (determined through the density) by the theoretical mass to determine the percent yield; 87.6\%


2290. Chapter 7 -
36. The conversion needed is $\mathrm{mol} \mathrm{Cr} \longrightarrow \mathrm{mol} \mathrm{H}_{3} \mathrm{PO}_{4}$. Then compare the amount of Cr to the amount of acid present. Cr is the limiting reactant.
37. $\mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}$ is the limiting reactant. percent yield $=86.56 \%$
38. Only four molecules can be made.
39. This amount cannot be weighted by ordinary balances and is worthless.
40. $3.4 \times 10^{-3} \mathrm{MH}_{2} \mathrm{SO}_{4}$
41. $9.6 \times 10^{-3} \mathrm{MCl}^{-}$
42. $22.4 \%$
43. The empirical formula is $\mathrm{BH}_{3}$. The molecular formula is $\mathrm{B}_{2} \mathrm{H}_{6}$.
44. 49.6 mL
45. 13.64 mL
46. 0.0122 M
47. 34.99 mL KOH
48. The empirical formula is $\mathrm{WCl}_{4}$.


2291. Chapter 8 -
1. The cutting edge of a knife that has been sharpened has a smaller surface area than a dull knife. Since pressure is force per unit area, a sharp knife will exert a higher pressure with the same amount of force and cut through material more effectively.
2. Lying down distributes your weight over a larger surface area, exerting less pressure on the ice compared to standing up. If you exert less pressure, you are less likely to break through thin ice.
3. $0.809 \mathrm{~atm} ; 82.0 \mathrm{kPa}$
4. $2.2 \times 10^{2} \mathrm{kPa}$
5. Earth: $14.7 \mathrm{lb} \mathrm{in}{ }^{-2}$; Venus: $1.30 \times 10^{3} \mathrm{lb} \mathrm{in}^{-2}$
6. (a) 101.5 kPa ; (b) 51 torr drop
7. (a) 264 torr; (b) $35,200 \mathrm{~Pa}$; (c) 0.352 bar
8. (a) 623 mm Hg ; (b) 0.820 atm ; (c) 83.1 kPa
9. With a closed-end manometer, no change would be observed, since the vaporized liquid would contribute equal, opposing pressures in both arms of the manometer tube. However, with an open-ended manometer, a higher pressure reading of the gas would be obtained than expected, since $P_{\text {gas }}=P_{\mathrm{atm}}+P_{\mathrm{vol}}$ liquid.
10. As the bubbles rise, the pressure decreases, so their volume increases as suggested by Boyle's law.
11. (a) The number of particles in the gas increases as the volume increases. (b) temperature, pressure
12. The curve would be farther to the right and higher up, but the same basic shape.
13. About 12.5 L
14. $3.40 \times 10^{3}$ torr
15. 12.1 L
16. 217 L
17. $8.190 \times 10^{-2} \mathrm{~mol} ; 5.553 \mathrm{~g}$


2291. Chapter 8 -
15. 12.1 L
16. 217 L
17. $8.190 \times 10^{-2} \mathrm{~mol} ; 5.553 \mathrm{~g}$
18. (a) $7.24 \times 10^{-2} \mathrm{~g}$; (b) 23.1 g ; (c) $1.5 \times 10^{-4} \mathrm{~g}$
19. 5561 L
20. 46.4 g
21. For a gas exhibiting ideal behavior:


2291. Chapter 8 -
22. (a) $1.85 \mathrm{~L} \mathrm{CCl}_{2} \mathrm{~F}_{2}$; (b) $4.66 \mathrm{~L} \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{~F}$
23. 0.644 atm
24. The pressure decreases by a factor of 3 .
25. $4.64 \mathrm{~g} \mathrm{~L}^{-1}$
26. 38.8 g
27. $72.0 \mathrm{~g} \mathrm{~mol}^{-1}$
28. $88.1 \mathrm{~g} \mathrm{~mol}^{-1} ; \mathrm{PF}_{3}$
29. 141 atm
30. $\mathrm{CH}_{4}: 276 \mathrm{kPa} ; \mathrm{C}_{2} \mathrm{H}_{6}: 27 \mathrm{kPa} ; \mathrm{C}_{3} \mathrm{H}_{8}: 3.4 \mathrm{kPa}$
31. Yes
32. 740 torr
33. (a) Determine the moles of HgO that decompose; using the chemical equation, determine the moles of $\mathrm{O}_{2}$ produced by decomposition of this amount of HgO ; and determine the volume of $\mathrm{O}_{2}$ from the moles of $\mathrm{O}_{2}$, temperature, and pressure. (b) 0.308 L
34. (a) Determine the molar mass of $\mathrm{CCl}_{2} \mathrm{~F}_{2}$. From the balanced equation, calculate the moles of $\mathrm{H}_{2}$ needed for the complete reaction. From the ideal gas law, convert moles of $\mathrm{H}_{2}$ into volume. (b) $3.72 \times 10^{3} \mathrm{~L}$
35. (a) Balance the equation. Determine the grams of $\mathrm{CO}_{2}$ produced and the number of moles. From the ideal gas law, determine the volume of gas. (b) $7.43 \times 10^{5} \mathrm{~L}$
36. 42.00 L


2291. Chapter 8 -
36. 42.00 L
37. (a) 18.0 L ; (b) 0.533 atm
38. $10.57 \mathrm{~L} \mathrm{O}_{2}$
39. $5.40 \times 10^{5} \mathrm{~L}$
40. $\mathrm{XeF}_{4}$
41. 4.2 hours
42. Effusion can be defined as the process by which a gas escapes through a pinhole into a vacuum. Graham's law states that with a mixture of two gases A and B: $\left(\frac{\text { rate } A}{\text { rate } B}\right)=\left(\frac{\text { molar mass of } B}{\text { molar mass of } A}\right)^{1 / 2}$. Both A and B are in the same container at the same temperature, and therefore will have the same kinetic energy:
$\mathrm{KE}_{\mathrm{A}}=\mathrm{KE}_{\mathrm{B}} \mathrm{KE}=\frac{1}{2} m v^{2}$
Therefore, $\frac{1}{2} m_{\mathrm{A}} v_{\mathrm{A}}^{2}=\frac{1}{2} m_{\mathrm{B}} v_{\mathrm{B}}^{2}$
$\frac{v_{\mathrm{A}}^{2}}{v_{\mathrm{B}}^{2}}=\frac{m_{\mathrm{B}}}{m_{\mathrm{A}}}$
$\left(\frac{v_{\mathrm{A}}^{2}}{v_{\mathrm{B}}^{2}}\right)^{1 / 2}=\left(\frac{m_{\mathrm{B}}}{m_{\mathrm{A}}}\right)^{1 / 2}$
$\frac{v_{\mathrm{A}}}{v_{\mathrm{B}}}=\left(\frac{m_{\mathrm{B}}}{m_{\mathrm{A}}}\right)^{1 / 2}$
43. $\mathrm{F}_{2}, \mathrm{~N}_{2} \mathrm{O}, \mathrm{Cl}_{2}, \mathrm{H}_{2} \mathrm{~S}$


2291. Chapter 8 -
43. $\mathrm{F}_{2}, \mathrm{~N}_{2} \mathrm{O}, \mathrm{Cl}_{2}, \mathrm{H}_{2} \mathrm{~S}$
44. $1.4 ; 1.2$
45. 51.7 cm
46. Yes. At any given instant, there are a range of values of molecular speeds in a sample of gas. Any single molecule can speed up or slow down as it collides with other molecules. The average speed of all the molecules is constant at constant temperature.
47. $\mathrm{H}_{2} \mathrm{O}$. Cooling slows the speeds of the He atoms, causing them to behave as though they were heavier.
48. (a) The number of collisions per unit area of the container wall is constant. (b) The average kinetic energy doubles. (c) The root mean square speed increases to $\sqrt{2}$ times its initial value; $u_{\text {rms }}$ is proportional to $\sqrt{\mathrm{KE}_{\text {avg }}}$.
49. (a) equal; (b) less than; (c) $29.48 \mathrm{~g} \mathrm{~mol}^{-1}$; (d) $1.0966 \mathrm{~g} \mathrm{~L}^{-1}$; (e) $0.129 \mathrm{~g} / \mathrm{L}$; (f) $4.01 \times 10^{5} \mathrm{~g}$; net lifting capacity $=384 \mathrm{lb}$; (g) 270 L ; (h) $39.1 \mathrm{~kJ} \mathrm{~min}^{-1}$
50. Gases C, E, and F
51. The gas behavior most like an ideal gas will occur under the conditions in (b). Molecules have high speeds and move through greater distances between collision; they also have shorter contact times and interactions are less likely. Deviations occur with the conditions described in (a) and (c). Under conditions of (a), some gases may liquefy. Under conditions of (c), most gases will liquefy.
52. $\mathrm{SF}_{6}$


2291. Chapter 8 -
52. $\mathrm{SF}_{6}$
53. (a) A straight horizontal line at 1.0; (b) When real gases are at low pressures and high temperatures, they behave close enough to ideal gases that they are approximated as such; however, in some cases, we see that at a high pressure and temperature, the ideal gas approximation breaks down and is significantly different from the pressure calculated by the ideal gas equation. (c) The greater the compressibility, the more the volume matters. At low pressures, the correction factor for intermolecular attractions is more significant, and the effect of the volume of the gas molecules on Z would be a small lowering compressibility. At higher pressures, the effect of the volume of the gas molecules themselves on Z would increase compressibility (see Figure 8.35). (d) Once again, at low pressures, the effect of intermolecular attractions on Z would be more important than the correction factor for the volume of the gas molecules themselves, though perhaps still small. At higher pressures and low temperatures, the effect of intermolecular attractions would be larger. See Figure 8.35. (e) Low temperatures


2292. Chapter 9 -
1. The temperature of 1 gram of burning wood is approximately the same for both a match and a bonfire. This is an intensive property and depends on the material (wood). However, the overall amount of produced heat depends on the amount of material; this is an extensive property. The amount of wood in a bonfire is much greater than that in a match; the total amount of produced heat is also much greater, which is why we can sit around a bonfire to stay warm, but a match would not provide enough heat to keep us from getting cold.
2. Heat capacity refers to the heat required to raise the temperature of the mass of the substance 1 degree; specific heat refers to the heat required to raise the temperature of 1 gram of the substance 1 degree. Thus, heat capacity is an extensive property, and specific heat is an intensive one.
3. (a) $47.6 \mathrm{~J} /{ }^{\circ} \mathrm{C} ; 11.38 \mathrm{cal}{ }^{\circ} \mathrm{C}^{-1}$; (b) $407 \mathrm{~J} /{ }^{\circ} \mathrm{C}$; $97.3 \mathrm{cal}{ }^{\circ} \mathrm{C}^{-1}$
4. $1310 \mathrm{~J} ; 313 \mathrm{cal}$
5. $7.15{ }^{\circ} \mathrm{C}$
6. (a) $0.390 \mathrm{~J} / \mathrm{g}{ }^{\circ} \mathrm{C}$; (b) Copper is a likely candidate.
7. We assume that the density of water is $1.0 \mathrm{~g} / \mathrm{cm}^{3}(1 \mathrm{~g} / \mathrm{mL})$ and that it takes as much energy to keep the water at $85^{\circ} \mathrm{F}$ as to heat it from $72^{\circ} \mathrm{F}$ to $85^{\circ} \mathrm{F}$. We also assume that only the water is going to be heated. Energy required $=7.47 \mathrm{kWh}$


2292. Chapter 9 -
8. lesser; more heat would be lost to the coffee cup and the environment and so $\Delta T$ for the water would be lesser and the calculated $q$ would be lesser
9. greater, since taking the calorimeter's heat capacity into account will compensate for the thermal energy transferred to the solution from the calorimeter; this approach includes the calorimeter itself, along with the solution, as "surroundings": $q_{\mathrm{rxn}}=-\left(q_{\text {solution }}+q_{\text {calorimeter }}\right)$; since both $q_{\text {solution }}$ and $q_{\text {calorimeter }}$ are negative, including the latter term $\left(q_{\mathrm{rxn}}\right)$ will yield a greater value for the heat of the dissolution
10. The temperature of the coffee will drop 1 degree.
11. $5.7 \times 10^{2} \mathrm{~kJ}$
12. $38.5^{\circ} \mathrm{C}$
13. -2.2 kJ ; The heat produced shows that the reaction is exothermic.
14. 1.4 kJ
15. 22.6. Since the mass and the heat capacity of the solution is approximately equal to that of the water, the two-fold increase in the amount of water leads to a two-fold decrease of the temperature change.
16. 11.7 kJ
17. $30 \%$
18. 0.24 g
19. $1.4 \times 10^{2}$ Calories
20. The enthalpy change of the indicated reaction is for exactly 1 mol HCL and 1 mol NaOH ; the heat in the example is produced by 0.0500 mol HCl and 0.0500 mol NaOH .
21. $25 \mathrm{~kJ} \mathrm{~mol}^{-1}$
22. $81 \mathrm{~kJ} \mathrm{~mol}^{-1}$
23. 5204.4 kJ
24. $1.83 \times 10^{-2} \mathrm{~mol}$
25. $-802 \mathrm{~kJ} \mathrm{~mol}^{-1}$


2292. Chapter 9 -
24. $1.83 \times 10^{-2} \mathrm{~mol}$
25. $-802 \mathrm{~kJ} \mathrm{~mol}^{-1}$
26. $15.5 \mathrm{~kJ} /{ }^{\circ} \mathrm{C}$
27. 7.43 g
28. Yes.
29. 459.6 kJ
30. $-494 \mathrm{~kJ} / \mathrm{mol}$
31. $44.01 \mathrm{~kJ} / \mathrm{mol}$
32. -394 kJ
33. 265 kJ
34. $90.3 \mathrm{~kJ} / \mathrm{mol}$
35. (a) $-1615.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$; (b) $-484.3 \mathrm{~kJ} \mathrm{~mol}^{-1}$; (c) 164.2 kJ ; (d) -232.1 kJ
36. $-54.04 \mathrm{~kJ} \mathrm{~mol}^{-1}$
37. $-2660 \mathrm{~kJ} \mathrm{~mol}^{-1}$
38. -66.4 kJ
39. -122.8 kJ
40. 3.7 kg
41. On the assumption that the best rocket fuel is the one that gives off the most heat, $\mathrm{B}_{2} \mathrm{H}_{6}$ is the prime candidate.
42. -88.2 kJ
43. (a) $\mathrm{C}_{3} \mathrm{H}_{8}(g)+5 \mathrm{O}_{2}(g) \longrightarrow 3 \mathrm{CO}_{2}(g)+4 \mathrm{H}_{2} \mathrm{O}(l)$; (b) 1570 L air; (c) $-104.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$; (d) $75.4^{\circ} \mathrm{C}$
44. (a) -114 kJ ;
(b) 30 kJ ;
(c) -1055 kJ


2292. Chapter 9 -
44. (a) -114 kJ ;
(b) 30 kJ ;
(c) -1055 kJ
45. The specific average bond distance is the distance with the lowest energy. At distances less than the bond distance, the positive charges on the two nuclei repel each other, and the overall energy increases.
46. The greater bond energy is in the figure on the left. It is the more stable form.
47.


2292. Chapter 9 -
$$
\begin{array}{lc}
\mathrm{HCl}(g) \longrightarrow \frac{1}{2} \mathrm{H}_{2}(g)+\frac{1}{2} \mathrm{Cl}_{2}(g) & \Delta H_{1}^{\circ}=-\Delta H_{\mathrm{f}[\mathrm{HCl}(g)]}^{\circ} \\
\frac{1}{2} \mathrm{H}_{2}(g) \longrightarrow \mathrm{H}(g) & \Delta H_{2}^{\circ}=\Delta H_{\mathrm{f}[\mathrm{H}(g)]}^{\circ} \\
\frac{1}{2} \mathrm{Cl}_{2}(g) \longrightarrow \mathrm{Cl}(g) & \Delta H_{3}^{\circ}=\Delta H_{\mathrm{f}[\mathrm{Cl}(g)]}^{\circ} \\
\hline \mathrm{HCl}(g) \longrightarrow \mathrm{H}(g)+\mathrm{Cl}(g) & \Delta H_{298}^{\circ}=\Delta H_{1}^{\circ}+\Delta H_{2}^{\circ}+\Delta H_{3}^{\circ} \\
D_{\mathrm{HCl}}^{\circ}=\Delta H_{298}^{\circ}=\Delta H_{\mathrm{f}[\mathrm{HCl}(g)]}^{\circ}+\Delta H_{\mathrm{f}[\mathrm{H}(g)]}^{\circ}+\Delta H_{\mathrm{f}[\mathrm{Cl}(g)]}^{\circ} \\
& =-(-92.307 \mathrm{~kJ})+217.97 \mathrm{~kJ}+121.3 \mathrm{~kJ} \\
& =431.6 \mathrm{~kJ}
\end{array}
$$

96. The $\mathrm{S}-\mathrm{F}$ bond in $\mathrm{SF}_{4}$ is stronger.
97.


2292. Chapter 9 -
96. The $\mathrm{S}-\mathrm{F}$ bond in $\mathrm{SF}_{4}$ is stronger.
97.

The $\mathrm{C}-\mathrm{C}$ single bonds are longest.
100. (a) When two electrons are removed from the valence shell, the Ca radius loses the outermost energy level and reverts to the lower $n=3$ level, which is much smaller in radius. (b) The +2 charge on calcium pulls the oxygen much closer compared with K , thereby increasing the lattice energy relative to a less charged ion. (c) Removal of the $4 s$ electron in Ca requires more energy than removal of the $4 s$ electron in $K$ because of the stronger attraction of the nucleus and the extra energy required to break the pairing of the electrons. The second ionization energy for K requires that an electron be removed from a lower energy level, where the attraction is much stronger from the nucleus for the electron. In addition, energy is required to unpair two electrons in a full orbital. For Ca , the second ionization potential requires removing only a lone electron in the exposed outer energy level. (d) In Al, the removed electron is relatively unprotected and unpaired in a $p$ orbital. The higher energy for Mg mainly reflects the unpairing of the $2 s$ electron.
102. (d)
104. $4008 \mathrm{~kJ} / \mathrm{mol}$; both ions in MgO have twice the charge of the ions in LiF; the bond length is very similar and both have the same structure; a quadrupling of the energy is expected based on the equation for lattice energy
106. (a) $\mathrm{Na}_{2} \mathrm{O}$; $\mathrm{Na}^{+}$has a smaller radius than $\mathrm{K}^{+}$; (b) BaS ; Ba has a larger charge than K ; (c) BaS ; Ba and S have larger charges; (d) BaS; S has a larger charge
108. (e)


2293. Chapter 10 -
1. Liquids and solids are similar in that they are matter composed of atoms, ions, or molecules. They are incompressible and have similar densities that are both much larger than those of gases. They are different in that liquids have no fixed shape, and solids are rigid.
2. They are similar in that the atoms or molecules are free to move from one position to another. They differ in that the particles of a liquid are confined to the shape of the vessel in which they are placed. In contrast,
a gas will expand without limit to fill the space into which it is placed.
3. All atoms and molecules will condense into a liquid or solid in which the attractive forces exceed the kinetic energy of the molecules, at sufficiently low temperature.
4. (a) Dispersion forces occur as an atom develops a temporary dipole moment when its electrons are distributed asymmetrically about the nucleus. This structure is more prevalent in large atoms such as argon or radon. A second atom can then be distorted by the appearance of the dipole in the first atom. The electrons of the second atom are attracted toward the positive end of the first atom, which sets up a dipole in the second atom. The net result is rapidly fluctuating, temporary dipoles that attract one another (e.g., Ar). (b) A dipole-dipole attraction is a force that results from an electrostatic attraction of the positive end of one polar molecule for the negative end of another polar molecule (e.g., ICI molecules attract one another by dipole-dipole interaction). (c) Hydrogen bonds form whenever a hydrogen atom is bonded to one of the more electronegative atoms, such as a fluorine, oxygen, or nitrogen atom. The electrostatic attraction between the partially positive hydrogen atom in one molecule and the partially negative atom in another molecule gives rise to a strong dipole-dipole interaction called a hydrogen bond (e.g., HF...HF ).
5. The London forces typically increase as the number of electrons increase.


2293. Chapter 10 -
5. The London forces typically increase as the number of electrons increase.
6. (a) $\mathrm{SiH}_{4}<\mathrm{HCl}<\mathrm{H}_{2} \mathrm{O}$; (b) $\mathrm{F}_{2}<\mathrm{Cl}_{2}<\mathrm{Br}_{2}$; (c) $\mathrm{CH}_{4}<\mathrm{C}_{2} \mathrm{H}_{6}<\mathrm{C}_{3} \mathrm{H}_{8}$; (d) $\mathrm{N}_{2}<\mathrm{O}_{2}<\mathrm{NO}$
7. Only rather small dipole-dipole interactions from C - H bonds are available to hold $n$-butane in the liquid state. Chloroethane, however, has rather large dipole interactions because of the $\mathrm{Cl}-\mathrm{C}$ bond; the interaction, therefore, is stronger, leading to a higher boiling point.
8. $-85^{\circ} \mathrm{C}$. Water has stronger hydrogen bonds, so it melts at a higher temperature.
9. The hydrogen bond between two hydrogen fluoride molecules is stronger than that between two water molecules because the electronegativity of $F$ is greater than that of $O$. Consequently, the partial negative charge on F is greater than that on O . The hydrogen bond between the partially positive H and the larger partially negative F will be stronger than that formed between H and O .
10. H -bonding is the principle IMF holding the protein strands together. The H -bonding is between the $\mathrm{N}-\mathrm{H}$ and $\mathrm{C}=\mathrm{O}$.
11. (a) hydrogen bonding, dipole-dipole attraction, and dispersion forces; (b) dispersion forces; (c) dipoledipole attraction and dispersion forces
12. The water molecules have strong intermolecular forces of hydrogen bonding. The water molecules are thus attracted strongly to one another and exhibit a relatively large surface tension, forming a type of "skin" at its surface. This skin can support a bug or paper clip if gently placed on the water.


2293. Chapter 10 -
13. Temperature has an effect on intermolecular forces: The higher the temperature, the greater the kinetic energies of the molecules and the greater the extent to which their intermolecular forces are overcome, and so the more fluid (less viscous) the liquid. The lower the temperature, the less the intermolecular forces are overcome, and so the less viscous the liquid.
14. (a) As the water reaches higher temperatures, the increased kinetic energies of its molecules are more effective in overcoming hydrogen bonding, and so its surface tension decreases. Surface tension and intermolecular forces are directly related. (b) The same trend in viscosity is seen as in surface tension, and for the same reason.
15. $1.7 \times 10^{-4} \mathrm{~m}$
16. The heat is absorbed by the ice, providing the energy required to partially overcome intermolecular attractive forces in the solid and causing a phase transition to liquid water. The solution remains at $0^{\circ} \mathrm{C}$ until all the ice is melted. Only the amount of water existing as ice changes until the ice disappears. Then the temperature of the water can rise.
17. We can see the amount of liquid in an open container decrease and we can smell the vapor of some liquids.
18. The vapor pressure of a liquid decreases as the strength of its intermolecular forces increases.
19. As the temperature increases, the average kinetic energy of the molecules of gasoline increases and so a greater fraction of molecules have sufficient energy to escape from the liquid than at lower temperatures.
20. They are equal when the pressure of gas above the liquid is exactly 1 atm.
21. approximately $95^{\circ} \mathrm{C}$
22. (a) At 5000 feet, the atmospheric pressure is lower than at sea level, and water will therefore boil at a lower temperature. This lower temperature will cause the physical and chemical changes involved in cooking
the egg to proceed more slowly, and a longer time is required to fully cook the egg. (b) As long as the air surrounding the body contains less water vapor than the maximum that air can hold at that temperature, perspiration will evaporate, thereby cooling the body by removing the heat of vaporization required to vaporize the water.


2293. Chapter 10 -
23. Dispersion forces increase with molecular mass or size. As the number of atoms composing the molecules in this homologous series increases, so does the extent of intermolecular attraction via dispersion forces and, consequently, the energy required to overcome these forces and vaporize the liquids.
24. The boiling point of $\mathrm{CS}_{2}$ is higher than that of $\mathrm{CO}_{2}$ partially because of the higher molecular weight of $\mathrm{CS}_{2}$; consequently, the attractive forces are stronger in $\mathrm{CS}_{2}$. It would be expected, therefore, that the heat of vaporization would be greater than that of $9.8 \mathrm{~kJ} / \mathrm{mol}$ for $\mathrm{CO}_{2}$. A value of $28 \mathrm{~kJ} / \mathrm{mol}$ would seem reasonable. A value of $-8.4 \mathrm{~kJ} / \mathrm{mol}$ would indicate a release of energy upon vaporization, which is clearly implausible.
25. The thermal energy (heat) needed to evaporate the liquid is removed from the skin.
26. 1130 kJ
27. (a) 13.0 kJ ; (b) It is likely that the heat of vaporization will have a larger magnitude since in the case of vaporization the intermolecular interactions have to be completely overcome, while melting weakens or destroys only some of them.
28. At low pressures and $0.005^{\circ} \mathrm{C}$, the water is a gas. As the pressure increases to 4.6 torr, the water becomes a solid; as the pressure increases still more, it becomes a liquid. At $40^{\circ} \mathrm{C}$, water at low pressure is a vapor; at pressures higher than about 75 torr, it converts into a liquid. At $-40^{\circ} \mathrm{C}$, water goes from a gas to a solid as the pressure increases above very low values.
29. (a) gas; (b) gas; (c) gas; (d) gas; (e) solid; (f) gas
30.


2293. Chapter 10 -
61. Yes, ice will sublime, although it may take it several days. Ice has a small vapor pressure, and some ice molecules form gas and escape from the ice crystals. As time passes, more and more solid converts to gas until eventually the clothes are dry.
63. (a)

(b)

(c)


2293. Chapter 10 -
(e) liquid phase (f) sublimation
65. (e) molecular crystals
67. Ice has a crystalline structure stabilized by hydrogen bonding. These intermolecular forces are of comparable strength and thus require the same amount of energy to overcome. As a result, ice melts at a single temperature and not over a range of temperatures. The various, very large molecules that compose butter experience varied van der Waals attractions of various strengths that are overcome at various temperatures, and so the melting process occurs over a wide temperature range.
69. (a) ionic; (b) covalent network; (c) molecular; (d) metallic; (e) covalent network; (f) molecular; (g)
molecular; (h) ionic; (i) ionic
71. $\mathrm{X}=$ ionic; $\mathrm{Y}=$ metallic; $\mathrm{Z}=$ covalent network
73. (b) metallic solid
75. The structure of this low-temperature form of iron (below $910^{\circ} \mathrm{C}$ ) is body-centered cubic. There is oneeighth atom at each of the eight corners of the cube and one atom in the center of the cube.
77. eight
79. 12
81. (a) $1.370 \AA$; (b) $19.26 \mathrm{~g} / \mathrm{cm}$
83. (a) $2.176 \AA$; (b) $3.595 \mathrm{~g} / \mathrm{cm}^{3}$
85. The crystal structure of Si shows that it is less tightly packed (coordination number 4) in the solid than Al (coordination number 12).
87. In a closest-packed array, two tetrahedral holes exist for each anion. If only half the tetrahedral holes are occupied, the numbers of anions and cations are equal. The formula for cadmium sulfide is CdS.
89. $\mathrm{Co}_{3} \mathrm{O}_{4}$


2293. Chapter 10 -
89. $\mathrm{Co}_{3} \mathrm{O}_{4}$
91. In a simple cubic array, only one cubic hole can be occupied be a cation for each anion in the array. The ratio of thallium to iodide must be 1:1; therefore, the formula for thallium is Tli.
93. $59.95 \%$; The oxidation number of titanium is +4 .
95. Both ions are close in size: $\mathrm{Mg}, 0.65 ; \mathrm{Li}, 0.60$. This similarity allows the two to interchange rather easily. The difference in charge is generally compensated by the switch of $\mathrm{Si}^{4+}$ for $\mathrm{Al}^{3+}$.
97. $\mathrm{Mn}_{2} \mathrm{O}_{3}$
99. $1.48 \AA$
101. $2.874 \AA$
103. $20.2^{\circ}$
105. $1.74 \times 10^{4} \mathrm{eV}$


2294. Chapter 11 -
1. A solution can vary in composition, while a compound cannot vary in composition. Solutions are homogeneous at the molecular level, while other mixtures are heterogeneous.
2. (a) The process is endothermic as the solution is consuming heat. (b) Attraction between the $\mathrm{K}^{+}$and $\mathrm{NO}_{3}{ }^{-}$ ions is stronger than between the ions and water molecules (the ion-ion interactions have a lower, more negative energy). Therefore, the dissolution process increases the energy of the molecular interactions, and it consumes the thermal energy of the solution to make up for the difference. (c) No, an ideal solution is formed with no appreciable heat release or consumption.
3. (a) ion-dipole forces; (b) dipole-dipole forces; (c) dispersion forces; (d) dispersion forces; (e) hydrogen bonding
4. Heat is released when the total intermolecular forces (IMFs) between the solute and solvent molecules are stronger than the total IMFs in the pure solute and in the pure solvent: Breaking weaker IMFs and forming stronger IMFs releases heat. Heat is absorbed when the total IMFs in the solution are weaker than the total of those in the pure solute and in the pure solvent: Breaking stronger IMFs and forming weaker IMFs absorbs heat.
5. Crystals of NaCl dissolve in water, a polar liquid with a very large dipole moment, and the individual ions become strongly solvated. Hexane is a nonpolar liquid with a dipole moment of zero and, therefore, does not significantly interact with the ions of the NaCl crystals.
6. (a) $\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}$ is a strong electrolyte, thus it should completely dissociate into $\mathrm{Fe}^{3+}$ and $\mathrm{NO}_{3}{ }^{-}$ions. Therefore, (z) best represents the solution. (b) $\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}(s) \longrightarrow \mathrm{Fe}^{3+}(a q)+3 \mathrm{NO}_{3}{ }^{-}(a q)$


2294. Chapter 11 -
7. (a) high conductivity (solute is an ionic compound that will dissociate when dissolved); (b) high conductivity (solute is a strong acid and will ionize completely when dissolved); (c) nonconductive (solute is a covalent compound, neither acid nor base, unreactive towards water); (d) low conductivity (solute is a weak base and will partially ionize when dissolved)
8. (a) ion-dipole; (b) hydrogen bonds; (c) dispersion forces; (d) dipole-dipole attractions; (e) dispersion forces
9. The solubility of solids usually decreases upon cooling a solution, while the solubility of gases usually decreases upon heating.
10. $40 \%$
11. 2.8 g
12. 2.9 atm
13. 102 L HCl
14. The strength of the bonds between like molecules is stronger than the strength between unlike molecules. Therefore, some regions will exist in which the water molecules will exclude oil molecules and other regions will exist in which oil molecules will exclude water molecules, forming a heterogeneous region.
15. Both form homogeneous solutions; their boiling point elevations are the same, as are their lowering of vapor pressures. Osmotic pressure and the lowering of the freezing point are also the same for both solutions.
16. (a) Find number of moles of $\mathrm{HNO}_{3}$ and $\mathrm{H}_{2} \mathrm{O}$ in 100 g of the solution. Find the mole fractions for the components. (b) The mole fraction of $\mathrm{HNO}_{3}$ is 0.378 . The mole fraction of $\mathrm{H}_{2} \mathrm{O}$ is 0.622 .


2294. Chapter 11 -
17. (a) $X_{\mathrm{Na}_{2} \mathrm{CO}_{3}}=0.0119 ; X_{\mathrm{H}_{2} \mathrm{O}}=0.988$; (b) $X_{\mathrm{NH}_{4} \mathrm{NO}_{3}}=0.0928 ; X_{\mathrm{H}_{2} \mathrm{O}}=0.907$; (c) $X_{\mathrm{Cl}_{2}}=0.192$; $X_{\mathrm{CH}_{2} \mathrm{CI}_{2}}=0.808 ;$ (d) $X_{\mathrm{C}_{5} \mathrm{H}_{9} \mathrm{~N}}=0.00426 ; X_{\mathrm{CHCl}_{3}}=0.997$
18. In a 1 M solution, the mole is contained in exactly 1 L of solution. In a 1 m solution, the mole is contained in exactly 1 kg of solvent.
19. (a) Determine the molar mass of $\mathrm{HNO}_{3}$. Determine the number of moles of acid in the solution. From the number of moles and the mass of solvent, determine the molality. (b) 33.7 m
20. (a) $6.70 \times 10^{-1} \mathrm{~m}$; (b) 5.67 m ; (c) 2.8 m ; (d) 0.0358 m
21. 1.08 m
22. (a) Determine the molar mass of sucrose; determine the number of moles of sucrose in the solution; convert the mass of solvent to units of kilograms; from the number of moles and the mass of solvent, determine the molality; determine the difference between the boiling point of water and the boiling point of the solution; determine the new boiling point. (b) $100.5^{\circ} \mathrm{C}$