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We just made a galvanic cell on a chemistry lesson using iron, iron sulfate , copper and copper sulfate.
We used a sponge soaked in $\ce{NaCl}$ solution as the salt bridge. The issue is that we measured a voltage way below the expected value and it was dropping quite fast.
The iron sulfate solution was yellow wh... |
I am a master distiller at a distillery and I am about to make some whiskey. First adding corn, cooking it and releasing it's starches. After that, will add in some malt, packed with enzymes to break down those starch molecules into sugars. My question is, what happens to the enzyme after it breaks down the starch? can... |
What happens to an enzyme after it breaks down a starch molecule? |
I found that $\ce{SO2 + 1/2 O2 -> SO3}$ when catalysed by platinum and heated to $\pu{700 ^\circ C}$. On the other hand I found that $\ce{SO3 -> SO2 + 1/2 O2}$ with same catalysator and temperature about $\pu{800 ^\circ C}$. How depends these two cases in real reaction? What controls which reaction will happen?
I t... |
Are these correct? |
So you were asked to write the electron configurations for the elements in the third energy level? I am a little confused. **I think elements do not reside on energy levels, electrons do.** OR, were you asked to write the electron configurations for the elements in the third period of the periodic table? If this is cas... |
Enzymes are a form of catalyst. Catalysts do not get consumed in a chemical reaction. I believe in reality, enzymes do degrade overtime and you need to replenish them overtime to keep the reaction efficient.
Can one (1) enzyme break down multiple starches? Sure.
I did not find specific literature on fermentation,... |
It should make sense that phosphorus has the positive charge,and gold itself has the negative charge in gold phosphide because phosphorus has a lower electronegativity than gold (phosphorus is 2.19, gold is 2.54). Is this true or not? |
Would gold have the negative charge in gold phosphide (AuP)? |
Great question!
When I was teaching, Anslyn and Dougherty was a decent text for this. Here are some general comments:
1. First, please note that you _cannot_ be sure about a mechanism. That's the real killer. You can devise experiments that are consistent with the mechanism but because you cannot devise and run a... |
Since you state, "We measured a voltage way below the expected value and **it was dropping quite fast**," it indicates a few things that could lead to those observations.
1. *How* did you measure voltage? If you used a low impedance voltmeter, it would show much lower voltage [because the impedance of the meter is low... |
Sr2+ is exactly the same as Kr, in terms of electrons and orbitals.
The only difference between the two, is that Sr2+ has a couple of extra protons in the nucleus (and probably a couple of extra neutrons too, but these don't influence ion/atom size).
Considering the extra 2x protons in the nucleus of Sr2+, and th... |
Why is Sr2+ ion bigger than Kr (atom)? |
What is the IUPAC rule for naming a Bicyclo compound with a benzene ring ? Are you required to state the number of dobule bonds by by adding something like 2,4,6 ene to the name or do benzene rings have a specific name ?
For Example:
[![Example Compound][1]][1]
[1]: https://i.stack.imgur.com/iXUVm.png
What ... |
How do you name a Bicyclo compound with a benzene ring? |
$\ce{Sr^2+}$ is exactly the same as $\ce{Kr}$, in terms of electrons and orbitals.
The only difference between the two, is that $\ce{Sr^2+}$ has a couple of extra protons in the nucleus (and probably a couple of extra neutrons too, but these don't influence ionic/atomic size).
Considering the two extra protons in... |
Why is strontium(II) ion bigger than krypton atom? |
Before answering my question, take a look at this example
$$\ce{2NOCl <=> 2NO + Cl2}$$
Let's suppose I have $\pu{2 mol/L}~\ce{NOCl},~\pu{2 mol/L}~\ce{NO}$, and $\pu{1 mol/L}~\ce{Cl2}$ in a closed system. If we were to calculate the equilibrium constant, it would be
$$K_c = \frac{(2)^2(1)}{(2)^2}$$
Now supp... |
I know that the constant $a$ represents the attractive forces between the molecules while the constant $b$ represents the size/repulsion between them. Does that mean that $a$ and $b$ are "inversely proportional" or are they independent of each other? If we have two gases and we can compare their sizes and attractive na... |
I have the following statements to mention before I pose my question
1) In compounds, we usually say that if the electronegativity of central metal is low then the bond angles would be lower.
2) Using the concept of hybridization we say that the compounds having more s-character will have higher electronegativity tha... |
Does higher bond angle mean higher electronegativity? |
I have the following statements to mention before I pose my question
1) In compounds, we usually say that if the electronegativity of central metal is low then the bond angles would be lower.
2) Using the concept of hybridization we say that the compounds having more $\mathrm s$-character will have higher electronega... |
I wonder if there exists a tool/script/algorithm to identify multiple molecules and/or atoms in a single XYZ or gaussian log file. As an example, imagine one does a single point calculation for the ethanol - Cl2 system, where the two molecules are placed next to each other at some distance. If one wants to detect all p... |
Like 'Jamie Gaidis' I was convinced at least some of the suspected $\ce{EtAc}$ is formed during the distillation step but presently I no longer believe that.
Instead I believe that compound is formed during fermentation and then concentrated into the distillate as the ternary azeotrope that 'Jamie Gaidis' suggests.
... |
I wonder if there exists a tool/script/algorithm to identify multiple molecules and/or atoms in a single XYZ or gaussian log file.
As an example, imagine one does a single point calculation for the ethanol-$\ce{Cl2}$ system, where the two molecules are placed next to each other at some distance. If one wants to dete... |
How to identify multiple molecules in a single xyz file? |
>How can I compare the van der Waals constant $a$ (the liquefication constant) for different compounds based on my knowledge of bonding in the compound?
Actually, as you indicated in the question, this comparison is not realistic since $a$ is unique to a particular compound/atom. As Chet Miller pointed out $a$ is de... |
Like 'Jamie Gaidis' I was convinced at least some of the suspected $\ce{EtAc}$ is formed during the distillation step but presently I no longer believe that.
Instead I believe that compound is formed during fermentation and then concentrated into the distillate as the ternary azeotrope that 'Jamie Gaidis' suggests.
... |
What is the difference between Lead Tetraacetate and sodium periodate reagent? |
What is the difference between lead tetraacetate and sodium periodate as reagents? |
The problem asks me to write which one is more stable- the keto or enol form. The compound given is this:<br>
[![enter image description here][1]][1]<br>
The solution says that the enol form would violate Bredt's Rule and would therefore be unstable:
[![enter image description here][2]][2]
<br>
But I am not entir... |
A textbook, describing a qualitative test for the $\ce{Al^3+}$ cation in which you use $\ce{NH4Cl}$ and $\ce{NH4OH}$ to precipitate $\ce{Al(OH)3}$, mentioned that the solubility of this precipitate decreases in the presence of the ammonium salt.
I sort of reasoned it out to the common-ion effect decreasing the $\ce{... |
As explained in [The Chemistry of Iron, Cobalt and Nickel: Comprehensive Inorganic Chemistry][1], at pages 1104 and 1105:
> almost all cobalt(III) complexes are low spin ... only with fluoride ions as ligands are high spin complexes ... found
In table 10, the book specifically lists $\ce[{Co(C_2O_4)_3}]^{3-}$... |
As explained in [The Chemistry of Iron, Cobalt and Nickel: Comprehensive Inorganic Chemistry][1], at pages 1104 and 1105:
> almost all cobalt(III) complexes are low spin ... only with fluoride ions as ligands are high spin complexes ... found
In table 10, the book specifically lists $\ce{[Co(C2O4)3]}^{3-}$ as... |
### Question
> Which one is more stable- the keto or enol form. The compound given is this:
>
>[![enter image description here][1]][1]<br>
### Solution
> The enol form would violate Bredt's Rule and would therefore be unstable. Hence the keto form is more stable
### My doubt
But I am not entirely conv... |
Like 'Jamie Gaidis' I was convinced at least some of the suspected $\ce{EtAc}$ is formed during the distillation step but presently I no longer believe that.
Instead I believe that compound is formed during fermentation and then concentrated into the distillate as the ternary azeotrope that 'Jamie Gaidis' suggests.
... |
How many boiling points does a mixture of liquids have? |
According to IUPAC, the official name for [molarity][1] is amount of substance concentration, and its symbol is $c$. The symbol for [molality][2] is $m$ or $b$, and the symbol for molar mass is $M$.
> what are the meaningful differences between molarity and molality?
Molality does not change with temperature beca... |
Charles' law says that at constant pressure the volume and temperature of an ideal gas are related as
$$\frac{V_1}{T_1}=\frac{V_2}{T_2}$$
If $V_2=V_1+dV$ and $T_2=T_1+dT$ then
$$\frac{V_1}{T_1}=\frac{V_1+dV}{T_1+dT}=\frac{V_1}{T_1}\left(\frac{1+dV/V_1}{1+dT/T_1}\right)$$
which can be rearranged into
$$\frac{d... |
Given the following pairs of samples, how do I distinguish between them?
1. benzamide and ethanamide
2. ethanoyl chloride and ethanoic anhydride
My Approach:
1. We could easily convert the amides to amines by reducing them with $\ce{LiAlH4}$. Now, the question reduces to identifying the methyl group against t... |
I have the following compounds and I want to compare the electron density on methyl group (basically inductive effects of $\ce{-N(+)R3}$ groups in both these compounds)
$\ce{Me-N+-(t-Bu)3}$ [A] and $\ce{Me-N+-(i-propyl)3}$ [B]
Now the only difference I see in these compounds is that due to steric effects the bond... |
Like 'Jamie Gaidis' I was convinced at least some of the suspected $\ce{EtAc}$ is formed during the distillation step but presently I no longer believe that.
Instead I believe that compound is formed during fermentation and then concentrated into the distillate as the ternary azeotrope that 'Jamie Gaidis' suggests.
... |
I want to compare the electron density on methyl group between tri‐*tert*‐butyl(methyl)azanium (**1**) and triisopropyl(methyl)azanium (**2**), i.e. essentially the inductive effects of $\ce{-\overset{+}{N}R3}$ groups.
$$\underset{\large\textbf{1}}{\ce{Me-\overset{+}{N}(t-Bu)3}}\qquad\underset{\large\textbf{2}}{\ce{... |
How do steric effects affect inductive effect in compounds with tetravalent nitrogen? |
I have a small confusion
If suppose HA is a acid then , HA gives H+ and A- ions in water.
The presence of H+ implies that the solution is acidic.
OK fine... but I came across that this solution will have OH- ions too.
I am confused, from where is it coming from ? Sources tell me that it could be from self ... |
Will the hybridisation of of $\ce{Co}$ in $\ce{[Co(ox)3]^3-}$ be $\mathrm{sp^3d^2}$ or $\mathrm{d^2sp^3}$? The question in which I found it has mentioned the answer to be $\mathrm{d^2sp^3}$ while I was thinking of the other one.
According to me, oxalate is a weak field ligand and it should not cause the pairing of e... |
Why is it that $\textrm{p}K_{\ce{a-HF}} \lt \textrm{p}K_{\ce{a-HCl}}\lt \textrm{p}K_{\ce{a-HBr}}\lt \textrm{p}K_{\ce{a-HI}}$, even though the electronegativity decreases down the column? The more electronegative the atom accompanying hydrogen, the lower the energy of the $\sigma^\ast$ bond. The lower the energy of the ... |
Why is it that
$$\mathrm{p}K_\mathrm{a}(\ce{HF}) < \mathrm{p}K_\mathrm{a}(\ce{HCl}) < \mathrm{p}K_\mathrm{a}(\ce{HBr}) < \mathrm{p}K_\mathrm{a}(\ce{HI}),$$
even though the electronegativity decreases down the group? The more electronegative the atom accompanying hydrogen, the lower the energy of the σ* bond. The ... |
I came across the following question in my orgo notes:
Outline the steps involved in the following transformation:
$C_2H_4$ to $(COOC_2H_5)_2$ (diethyl oxalate)
I am familiar with the transformation of $C_2H_4$ to $CH_3COOC_2H_5$ (ethyl acetate) by first converting to ethanol (using water and an acid) then using... |
I came across the following question in my orgo notes:
Outline the steps involved in the following transformation:
$\ce{C2H4}$ to $\ce{(COOC2H5)2}$ (diethyl oxalate)
I am familiar with the transformation of $\ce{C2H4}$ to $\ce{CH3COOC2H5}$ (ethyl acetate) by first converting to ethanol (using water and an acid) ... |
So I know that 301 Stainless steel was chosen for the SpaceX Starship rocket as it can handle high temperature differences. **Question:** What about this alloy makes the steel harden when it gets colder? |
Sorry if this seems like a silly question but it has me confused a lot. So I have just started taking Chemical Reaction Engineering, and was studying about continuous-stirred tank reactor (CSTR).
So in my textbook it's stated that "It is normally operated at steady state and is assumed
to be perfectly mixed; conseq... |
1. Convert ethene to ethanol
Ethene is mixed with steam and passed over a catalyst consisting of solid silicon dioxide coated with phosphoric(V) acid. The temperature used is 300 °C and the pressure is about 60 to 70 atmospheres. ([Source][1])
$$\ce{CH2=CH2 + H2O <=>[H3PO4] CH3CH2OH}$$
2. React the ethanol ... |
So I know that 301 stainless steel was chosen for the SpaceX Starship rocket as it can handle high temperature differences.
**Question:**
What about this alloy makes the steel harden when it gets colder? |
So I know that 301 stainless steel was chosen for the SpaceX Starship rocket as it can handle high temperature differences.
What about this alloy makes the steel harden when it gets colder? |
>How can I compare the van der Waals constant $a$ (the liquefication constant) for different compounds based on my knowledge of bonding in the compound?
Actually, as you indicated in the question, this comparison is not realistic since $a$ is unique to a particular compound/atom. As Chet Miller pointed out $a$ is de... |
What is the IUPAC rule for naming a bicyclo compound with a benzene ring? Are you required to state the number of double bonds by adding something like 2,4,6-ene to the name or do benzene rings have a specific name ?
For example:
[![enter image description here][1]][1]
What will this compound be named? Will ... |
How do you name a bicyclo compound with a benzene ring? |
I came across the following question in my orgnic notes:
> Outline the steps involved in the following transformation:
$\ce{C2H4}$ to $\ce{(COOC2H5)2}$ (diethyl oxalate)
I am familiar with the transformation of $\ce{C2H4}$ to $\ce{CH3COOC2H5}$ (ethyl acetate) by first converting to ethanol (using water and an... |
Dissolution of urea in water:Endothermic or Exothermic? |
Is the change in enthalpy (ΔH) for dissolution of urea in water positive or negative? |
How to calculate the quantum yield of a photochemical process? |
Primary, secondary and tertiary alcohols can easily be distinguished by using reagent tests such as:
- The triiodomethane test for $\ce{R-CH(CH3)OH}$ alcohols.
- Lucas' reagent to distinguish between three alcohol groups.
- A combination of reagents to distinguish between three alcohols. For example, dichromate... |
Is it possible to distinguish between cyclohexanol and cyclohex-2-en-1-ol with simple chemical test? |
For atoms and molecules with more than one electron, the wavefunction cannot be written as a single Slater determinant, so the ground-state configuration of (the atom or molecule in question) is defined as the configuration whose Slater determinant has the largest (in absolute value) coefficient in the configuration in... |
Is an element's "atomic electron configuration" EXACTLY equal to the term with the largest coefficient in the CI series of the neutral atom? |
>I have that $\pu{100 ml}$ of an aqueous solution containing $\pu{1.0 mM}$ $\ce{H2O2}$, $\pu{100 mM}$ $\ce{CH3OH}$ and $\pu{200 mM}$ DMSO are exposed to monochromatic light with a wavelength of $300$ nm. The incident light intensity is $\pu{2mW/cm2}$ and the exposed area is $\pu{4cm2}$. The absorbance of the solution ... |
If an exercise asks for the hybridisation state of a coordinate complex (ion in solution) consisting of a central cobalt atom surrounded by $\ce{NH_3}$ ligands, and neither coordination number or complex ion is given, how do you decide which configuration will occur?
The answer is that in a solution this will form a... |
In general soft nucleophiles do 1,4 conjugate addition to a carbonyl carbon under thermodynamic control. Will soft nucleophiles like organo-cuprates undergo 1,4 addition if the β site is more sterically hindered than the carbonyl carbon. Will 1,4-addition still form the more favorable product?
For example, if I cons... |
Will "soft nucleophiles" undergo 1,4-conjugate addition if β site is sterically hindered? |
Will "soft nucleophiles" undergo 1,4-conjugate addition even if β site is sterically hindered? |
In a nitro-Mannich reaction, if we deprotonate a nitroalkane species with a strong base, then add acetic acid followed by an imine species, the reaction still proceeds giving the $\beta$-nitroamine.
Why is that the case and why wouldn’t we get protonation of the nitro anion species hindering a subsequent reaction w... |
Why doesn't acetic acid affect the formation of beta-nitroamine in nitro-Mannich reaction? |
Please help me, a mathematician doing his elective course on Physical Chemistry, out with this very simple question: why does the relation between enthalpy and heat $$\Delta H = \Delta U + p \Delta V = \Delta Q$$ hold only under constant pressure? With the integral definition of work, couldn't one just as well write $$... |
Why is enthalpy change = heat change only for constant pressure? |
Came across a few graphs that represent the mutual solubility of two compounds in a solvent, for eg, solubility of $\ce{KCl}$, and $\ce{NaCl}$ in $\ce{H2O}$.
On these particular graphs, I can see $x$ axis as $\pu{g/100ml}$ of $\ce{KCl}$, on $y$ axis it has $\pu{g/100ml}$ of $\ce{NaCl}$, and the graph has multiple ... |
Please help me, a mathematician doing his elective course on Physical Chemistry, out with this very simple question: why does the relation between enthalpy and heat $$\Delta H = \Delta U + p\,\Delta V = \Delta Q$$ hold only under constant pressure? With the integral definition of work, couldn't one just as well write $... |
What makes selectivity other than activation energy? |
Wikipidia quotes a melting point of 1713C for sand.
I went on the beach to get some sand. I assume it's a mix of all kinds of stuff.
I'd like to get rid of plastics & organics by heating it up.
What temperature can I bring it up to before the smallest particles start to agglomerate? What temperature would yo... |
Trial by fire: Safely heating sand without it agglomerating? |
Sand is not available as a reagent grade chemical, but rather is mineral origin particles of a size between 0.074 and 4.75 millimeters. Gravel is bigger, silt is smaller.
Pure silica (SiO$_2$) may melt at 1713$^o$, but the melting point of real sand is given as 1500 to 1610, and you can probably find some numbers ou... |
Wikipidia quotes a melting point of 1713C for sand.
I went on the beach to get some sand. I assume it's a mix of all kinds of stuff.
The finality is to prepare a big pile of clean sand to use as filtering aid above paper filter (among other uses).
I'd like to get rid of plastics & organics by heating it up.
... |
I am calculating $K_\mathrm{a}$ and percent dissociation of acetic acid being diluted to $\pu{1.00 \times 10^{-1} M}$, $\pu{1.00 \times 10^{-2} M}$, and $\pu{1.00 \times 10^{-4} M}$.
The $\mathrm{pH}$ goes up as the weak acid is diluted, which is to be expected.
The % dissociation is inversely related to the init... |
I've got a question that should be simple enough but I must be doing something very wrong.
A 10mL sample of H2SO3 is neutralized by 18.6mL of a 0.10M strong base. Find the concentration of the acid.
My solution:
1. Given the information, I calculate 1.86E-3 mol of OH- used for this reaction, so an equivalent ... |
Concentration of weak acid neutralized by strong acid? |
So all of the other group 16 elements (besides oxygen) have some type of carbohydrate but the oxygen gets replaced with sulfur,selenium or tellurium,so polonium should have an alcohol like polonol for example (CH4Po) ,or am I wrong? |
Is there polonium versions of where oxygen would be in place? (Organopolonium chemistry) |
As far as I could remember, in the same period, a bond to a more electronegative atom implies in a more polar and stronger bond, due to the greater ionic character. However the bond dissociation energy for the C-X series follows the order: C-F > C-O > C-C > C-N. The same for H-X: H-F > H-O > H-C > H-N.
Why are the b... |
As far as I could remember, in the same period, a bond to a more electronegative atom implies in a more polar and stronger bond, due to the greater ionic character. However the bond dissociation energy for the C-X series follows the order: C-F > C-O > C-C > C-N. The same for H-X: H-F > H-O > H-C > H-N.
Why are the b... |
$\ce{Sr^2+}$ is exactly the same as $\ce{Kr}$, in terms of electrons and orbitals.
The only difference between the two, is that $\ce{Sr^2+}$ has a couple of extra protons in the nucleus (and probably a couple of extra neutrons too, but these don't influence ionic/atomic size).
Considering the two extra protons in... |
[![Figure][1]][1]
Hello,
I will list the questions directly, if you want to know details please read below.
As in the figure, we have water+baking soda in a plastic cup, there are 2 versions in figure that affects LED's brightness and current that flows in circuit.
1. In 1st version of figure, LED is brigh... |
So all of the other group 16 elements (besides oxygen) have some type of carbohydrate, in which the oxygen gets replaced with sulfur, selenium or tellurium. So, does polonium have an alcohol like polonol for example ($\ce{CH4Po}$), or am I wrong? |
> Wouldn't heteropoly-acid and homopoly-acids pair be morphologically more accurate (than heteropoly-acid and isopoly-acids)?
I completely agree with andselisk of this suggestion because the former makes more sense than latter in this regards. For instance, as correctly pointed out in the question, the IUPAC Red Boo... |
>Compare the **nucleophilic strengths** of the following two compounds:
<img src="https://i.stack.imgur.com/QXgcA.png">
According to me it should be the second one, that is, (2R,6R)-2,6-dimethyltetrahydropyran because the methyl groups would exert +I effect which would increase the electron density on the oxygen at... |
I came across the following while going through my textbook
> The standard enthalpy of reaction is related to bond enthalpies of reactants and products in gas phase reactions as: $$\Delta H^{\circ}_r = \Sigma(\textrm{bond enthalpies})_{\textrm{reactants}}-\Sigma(\textrm{bond enthalpies})_{\textrm{products}}$$ If we u... |
What is the difference between bond enthalpy and bond formation enthalpy? |
[![enter image description here][1]][1]
I understand the use of the internal standard methodology, however I am unsure which values I should use in the equation as although I have been given the internal standard solution I also have been given the second standard solution of both codeine and morphine.
The ques... |
I have the formula $\ce{Co(C2O4)*H2O}$ in a reaction that forms cobalt oxide $\ce{Co3O4}$ – My data here says that my oxalate hydrate weighed 0.3283 g and my product oxide weighed 0.1158 g which I have calculated as 0.1158 × (176.79 g cobalt / 240.79 g cobalt oxide) to equal 0.08502 g of cobalt in the original sample. ... |
You seem to be asking the question "Why does this intramolecular hydrogen bonding not cause a considerable effect to the $\ce{pKa}$ values of these compounds?"
<br/>
<br/>
TL;DR That is because this type of bonding is only present in this conformer only and this type of conformer of the compound 2-FluoroBenzoic acid... |
Have you taken into account that there is a $\ce{-CH3}$ group attached to the top N which has +I effect i.e., electron donating effect?
$\ce{-CH3}$ group will destabilize the negative charge on N formed after the release of proton.
Electron releasing group decreases acidic strength of a compound. So in this quest... |
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