instruction stringlengths 15 21.8k |
|---|
What is average rate? What is instantaneous rate? How do you find these? My teacher described finding the tangent to a graph. I am not sure what is meant by this.
Thanks! |
The $pK_a$ is the $-log_{10}$ of the $k_a$ value for the disassociation of an acid. So how do you get a $pK_a$ value for a base? The base produces no hydrogen ions so can't you only have a $pK_b$? |
The $pK_a$ is the $-\log_{10}$ of the $k_a$ value for the disassociation of an acid. So how do you get a $pK_a$ value for a base? The base produces no hydrogen ions so can't you only have a $pK_b$? |
How do I solve problems where I'm asked for $\triangle H$ and given $\triangle H$ values for equations with the involved elements? For example:
Find the $\triangle H$ of the following reaction:
$C + O_{2} \Longrightarrow CO _{2}$, given:
$SrO + O _{2} \Longrightarrow SrCO_{3}$**;** $\triangle H = -234 kJ$
$2... |
What is average rate? What is instantaneous rate? How do you find these? My teacher described finding the tangent to a graph. I am not sure what is meant by this.
|
How do you find the average rate and instantaneous rate given a kinetics plot? |
How do I solve problems where I'm asked for $\triangle H$ and given $\triangle H$ values for equations with the involved elements? For example:
Find the $\triangle H$ of the following reaction:
$C + O_{2} \Longrightarrow CO _{2}$, given:
$SrO + CO _{2} \Longrightarrow SrCO_{3}$ **;** $\triangle H = -234 kJ$
... |
I don't understand question 6, although I took notes and the professor mentioned an explanation in class. Can someone please help using easier terms?
![enter image description here][1]
[1]: https://i.stack.imgur.com/L2ACP.jpg |
Diel's Alder reaction. Which will react fastest? Need explanation. |
How do I solve problems where I'm asked for $\triangle H$ and given $\triangle H$ values for equations with the involved elements? For example:
Find the $\triangle H$ of the following reaction:
$C + O_{2} \Longrightarrow CO _{2}$, given:
$SrO + CO _{2} \Longrightarrow SrCO_{3}$ **;** $\triangle H = -234 kJ$
... |
How do I solve problems where I'm asked for $\Delta H^\circ_f$ and given $\Delta H^\circ_f$ values for equations with the involved elements? For example:
Find the $\Delta H^circ_f$ of the following reaction:
$\ce{C + O_{2} -> CO _{2}}$, given:
$\ce{SrO + CO _{2} -> SrCO_{3}}$ **;** $\Delta H^\circ_f = -234 \tex... |
How do I solve problems where I'm asked for $\Delta H^\circ_f$ and given $\Delta H^\circ_f$ values for equations with the involved elements? For example:
Find the $\Delta H^{circ_f}$ of the following reaction:
$\ce{C + O_{2} -> CO _{2}}$, given:
$\ce{SrO + CO _{2} -> SrCO_{3}}$ **;** $\Delta H^\circ_f = -234 \t... |
How do I solve problems where I'm asked for $\Delta H^\circ_f$ and given $\Delta H^\circ_f$ values for equations with the involved elements? For example:
Find the $\Delta H^\circ_f$ of the following reaction:
$\ce{C + O_{2} -> CO _{2}}$, given:
$\ce{SrO + CO _{2} -> SrCO_{3}}$ **;** $\Delta H^\circ_f = -234 \te... |
This is what I understand so far:
The concept of a buffer is to minimize any swings in pH. In order to do this you need to create a solution with both acidic and basic compounds.
To create one, you start with an acid:
$\ce{HA + H2O -> A- + H3O+}$
[My first question is why for buffers the acid needs to be weak... |
Can someone please explain buffers to me? |
a) The compound can rotate into a trans configuration that is not suitable for Diels Alder
b) The compound is locked into a cis configuration that is favorable. Furthermore, a carbon group is slightly electron donating
c) The compound has an electron withdrawing group.
d) What compound is that?
Comment: Nor... |
Writing out the equilibrium expression for a weak acid in solution:
$$[\ce{H3O+}] = K_a\frac{[HA]}{[A^-]} $$
Buffers need to keep the concentration of the weak acid to it's conjugate base similar in order for it be effective.
Let's say you add a small amount of base. Some of the $HA$ molecules are converted i... |
Reaction of a vicinal diol with acetone? |
I don't understand question 6, although I took notes and the professor mentioned an explanation in class.
Can someone please help using easier terms?
![enter image description here][1]
[1]: https://i.stack.imgur.com/L2ACP.jpg |
> A dilute solution of which acid is most likely to produce a reduction
> product other than $\rm H_{2}$ when it reacts with a metal?
> (A) $\ce{HF}$
> (B) $\ce{HCl}$
> (C) $\ce{HNO3} $
> (D) $\ce{H2SO4}$
> $\tiny{\text{Question from 2012 local chemistry olympiad}}$
The given answer is (C), $\ce... |
Why does $\rm HNO_3$ not give off $\rm H_2$ when reacting with $\rm Cu$? |
> A dilute solution of which acid is most likely to produce a reduction
> product other than $\ce{H_{2}}$ when it reacts with a metal?
> (A) $\ce{HF}$
> (B) $\ce{HCl}$
> (C) $\ce{HNO3} $
> (D) $\ce{H2SO4}$
> $\tiny{\text{Question from 2012 local chemistry olympiad}}$
The given answer is (C), $\c... |
Why does HNO3 not give off H2 when reacting with Cu? |
I made some pH indicator by boiling and straining cabbage juice and in an effort to keep it from spoiling for a while without having to store it at fridge temperatures I added some wine making stabiliser which consists primarily of Sodium Metabisulphite. I had previously tested some of it to check if adding it would af... |
Writing out the equilibrium expression for a weak acid in solution:
$$[\ce{H3O+}] = K_a\frac{[HA]}{[A^-]}$$
Buffers need to keep the concentration of the weak acid to it's conjugate base similar in order for it be effective.
Let's say you add a small amount of base. Some of the $HA$ molecules are converted in... |
Is there any organic compound that has another type of bonds than the covalent bonds? |
Can an organic compound have an ionic bond? |
for example Oxepane is a 7-Atom Ring can there be 8-Atom Ring or 9-Atom Ring .. or million-Atom Ring to infinity? |
Is there a (carbon) hetrocyclic compounds named from number three to infinity? |
Is there a (carbon) heterocyclic compounds named from number three to infinity? |
As i understand, when brushing hair, some electron transfer from hair to the comb. Thus, make the comb have different charged from hair and they attract each other.
It's look likely what i have learn from school about ionic bond. One electron from Na is transfer to F and so we have NaF . Isn't it ??? Sorry for my stup... |
Comb and hair, is that an example for ionic boding? |
As i understand, when brushing hair, some electron transfer from hair to the comb. Thus, make the comb have different charged from hair and they attract each other.
It's look likely what i have learn from school about ionic bond. One electron from Na is transfer to F and so we have NaF . Isn't it ??? |
Number of molecules and atoms are same in a gas, how? |
I have a pot with some (bottled) water and added (sea) salt. It has a pencil (graphite) and tin foil (aluminum). The pencil is connected to the positive outlet of a solar panel and the tinfoil is connected to the negative outlet of the solar panel (effectively 'charging' the electrolytic cell).
To ensure I don't com... |
Electrolytic cell chemical composition during/after charging? |
In school, we did an experiment using fat and KOH to create 'soft' soap.
Afterwards, we added NaOH to change it into 'hard' soap.
I read on multiple places on the internet that the difference between using Potassium and Sodium is what determines if it becomes a 'hard' soap or 'soft' soap.
Am I correct in the n... |
'Hard' soap vs. 'Soft' soap: Why do they work this way? |
http://books.google.com/books/about/Crystal_Growth_in_Gels.html?id=pQ-JuNXEL6wC <BR>
The classic text. Set them up, come back in a few weeks. (Potentially any gel - polyacrylamide, agarose, agar, gelatin...) Meanwhile,
The Prussian Blue prep works across the transition metals, with different colors. Alas, it ... |
In school, we did an experiment using fat and $\ce{KOH}$ to create 'soft' soap.
Afterwards, we added $\ce{NaOH}$ to change it into 'hard' soap.
I read on multiple places on the internet that the difference between using Potassium and Sodium is what determines if it becomes a 'hard' soap or 'soft' soap.
Am I co... |
Can hydrocarbon organic compounds have a type of bonds other than covalent bonds? |
Can a hydrocarbon organic compound contain an ionic bond? |
I dont understand the concept of n factor at all. Why is it important? |
How do we calculate N factor and why is it useful in calulations? |
With the following setup: plastic container, water (impure), pencil (anode), tin foil (aluminum, cathode) and solar panels supplying electrical charge (roughly 36v at about 400-800ma), with the intention of producing lye via electrochemistry:
1) Would it be possible to produce the right kind of lye to a level suffic... |
Does somebody know how many lumens we get from lighting 1 gram of flash powder in pure oxygen (or normal) environment? I'm thinking about ${KClO_4} $ (60%) + $Al$ (40%) flash powder and quite fast flaming due to lighting it up with electricity. |
Do you have an idea how can be flaming of flash powder (probably ${KClO_4} $ (60%) + $Al$ (40%) ) can be speeded up? Of course we consider the pure oxygen-in-air conditions. So how? With some kind of catalyst?
Thanks. |
There are some different applications.
For one, it tells you how many times an acid can lose a proton. For instance you can have a diprotic ("with 2 H+") molecule, with n=2. For instance, H2SO4, deprotonates to HSO4-, which can then go to SO4(-2).
Why is that important? Take an acidic reaction with H2SO4. If the... |
Basically, yes, by common terms, soft soap has K+ and hard soap has Na+.
They are both alkali metals, but K+ is below Na+ on the periodic table so maybe we should consider periodicity trends. As you go down a table the atoms become more reactive, so K+ is more likely to react with polar parts of water than Na+. Here... |
Do you have an idea how can be flaming of flash powder (probably $\ce{KClO_4} $ (60%) + $\ce{Al}$ (40%) ) can be speeded up? Of course we consider the pure oxygen-in-air conditions. So how? With some kind of catalyst?
Thanks. |
Does somebody know how many lumens we get from lighting 1 gram of flash powder in pure oxygen (or normal) environment? I'm thinking about $\ce{KClO_4} $ (60%) + $\ce{Al}$ (40%) flash powder and quite fast flaming due to lighting it up with electricity. |
Which of these reduction reagents would me most appropriate to yield this product? |
What is a product of water ionization ? |
I'm learning about how to recognition whether a bond is ionic bonding or covalent bonding.
What i have now is a formula:
- Electronegativty difference = 0 then its nonpolar
- Electronegativty difference is more than 0 but less than 1.7 are polar covalent
- Electronegativty difference greater than 1.7 are ionic
... |
Why electronegativty difference greater than 1.7 are ionic? |
I'm learning about how to recognise whether a bond is ionic or covalent bonding.
What I have now is a formula:
- Electronegativity difference = 0 then its nonpolar
- Electronegativity difference is more than 0 but less than 1.7 are polar covalent
- Electronegativity difference greater than 1.7 are ionic
But ... |
Why electronegativity difference greater than 1.7 are ionic? |
Basically, yes, by common terms, soft soap has $\ce{K+}$ and hard soap has $\ce{Na+}$.
They are both alkali metals, but $\ce{K+}$ is below $\ce{Na+}$ on the periodic table so maybe we should consider periodicity trends. As you go down a table the atoms become more reactive, so $\ce{K+}$ is more likely to react with ... |
Aromaticity might be viewed as resonance stabilzation energy, NMR shift, or altered reactivity. Here is a way of measuring its change among related systems,
Chem. Commun. 48, 8144 (2012) <BR>
J. Am. Chem. Soc. 131, 189 (2009) <BR>
J. Am. Chem. Soc. 127, 16251 (2005) <BR>
J. Org. Chem. 67, 8798 (2002) <BR>
J. A... |
What will be happen if we add a solution of ammonia and water over bad quality iron? Some reaction will take place. Rust will be created on it.
Here is the main question:
**As a chemist** how do you understand after three to four days that I pour ammonia solution on it? Assume that this three or four days it was ... |
I am not a Chemist or did not learn chemistry as a student. I have faced this phenomena from a natural visualization. So this question.
**Experiment:** What will be happen if we add a solution of ammonia and water over bad quality iron? When it shall be dried I shall pour again. Several day It shall be done regularl... |
I am reading this [wikipedea article](http://en.wikipedia.org/wiki/Crisscross_method). I do not understand this article. What I do not understand is:
>suppose we have two elements $X$ and $Y$ having oxidation numbers $x$ and $y$ respectively. Can we prove that the compound formed will be $X_yY_x$.
I tried to un... |
I am reading this [wikipedea article](http://en.wikipedia.org/wiki/Crisscross_method). I do not understand this article. What I do not understand is:
>suppose we have two elements $X$ and $Y$ having oxidation numbers $x$ and $y$ respectively. Can we prove that the compound formed will be $X_yY_x$.
I tried to un... |
In a typical household, the following surfactants are found, among others:
* Soap / handwash
* Shower gel
* Shampoo
* Dishwashing agent
* Washing powder / liquid
From my understanding, the role of all these is to lower the surface tension between water and fatty acids, enabling one to "wash" things.
Are th... |
What are the differences between the various household surfactants? |
What is LE (plant contents)? |
From your diagram, $R_G$ is the recycled gas - the hydrogen that has not been consumed plus the methane that has been produced. $R_L$ is the recycled liquid - the unreacted toluene. Both go back into the mixer with fresh toluene added at the rate given and fresh hydrogen added to bring the mole ratio of hydrogen to tol... |
From your diagram, $R_G$ is the recycled gas - the hydrogen that has not been consumed plus the methane that has been produced. $R_L$ is the recycled liquid - the unreacted toluene. Both go back into the mixer with fresh toluene added at the rate given and fresh hydrogen added to bring the mole ratio of hydrogen to tol... |
Concentration of aqueous solution Mg(so4)2 is 0.001 moldm^-3.
Find out the concentration of solution and the concentation of Mg2+ ion in *PPm*
How to do this? How to find moles in ppm .
If any one clearly describe ,it would be great |
The concentration of an aqueous solution of $\ce{Mg(SO4)2}$ is $0.001\, \textrm{mol} \cdot \textrm{dm}^{-3}$.
Find out the concentration of solution and the concentation of $\ce{Mg^{2+}}$ ion in *ppm*.
How to do this? How to find moles in ppm?
If anyone could clearly describe, it would be great. |
Hiho.
I have a question concerning this image (Chemistry, Catherine E. Housecroft et al., Pearson Education, 2010).
![diagram of in-phase and out-of-phase energies as a function of distance in H2][2]
In the text, it states the following:
>"Each of the new molecular wavefunctions, $\Psi$(in-phase) and $\Psi$(o... |
Molecular systems - are in a simple count systems made up of molecules. But almost every system, surrounding us are molecular than. Considering the molecular systems in terms of chemistry compels us, firstly, impose dimensional constraints on the molecular system (which?), molecular system could not be macroscopic (How... |
What is the range of sizes for molecular systems? |
In Gallium Arsenide ($\ce{GaAs}$) the Gallium atom has an oxidation state of $\ce{+3}$ and the Arsenic atom has an oxidation state of $\ce{-3}$.
$\ce{Ga5As3}$ can't exist because here you suppose that arsenic has an oxidation state of $\ce{-5}$, what isn't correct : Arsenic can only have a positive $\ce{+5}$ charge... |
In Gallium Arsenide ($\ce{GaAs}$) the Gallium atom has an oxidation state of $\ce{+3}$ and the Arsenic atom has an oxidation state of $\ce{-3}$.
$\ce{Ga5As3}$ can't exist because here you suppose that arsenic has an oxidation state of $\ce{-5}$, what isn't correct : Arsenic can only have a positive $\ce{+5}$ charge... |
In Gallium Arsenide ($\ce{GaAs}$) the Gallium atom has an oxidation state of $\ce{+3}$ and the Arsenic atom has an oxidation state of $\ce{-3}$.
$\ce{Ga5As3}$ can't exist because here you suppose that arsenic has an oxidation state of $\ce{-5}$, what isn't correct : Arsenic can only have a positive $\ce{+5}$ charge... |
I am reading this [wikipedia article](http://en.wikipedia.org/wiki/Crisscross_method) that I don't understand. What I don't understand is:
>suppose we have two elements $X$ and $Y$ having oxidation numbers $x$ and $y$ respectively. Can we prove that the compound formed will be $X_yY_x$.
I tried to understand th... |
I don't understand the concept of n factor at all. Why is it important?
I know that its something dependent upon the oxidation number for example n factor of Na would be 1 since it has oxidation of one. For acid and bases we look at the replaceable H+ or Oh- present on them. Apart from this, i didn't really understand... |
I don't understand the concept of N factor at all. Why is it important?
I know that it is something dependent upon the oxidation number, for example N factor of Na would be 1 since it has oxidation of one.
For acid and bases we look at the replaceable $\ce{H+}$ or $\ce{OH-}$ present on them.
Apart from this,... |
I'm a mathematician who's currently teaching a course on differential equations. Though I don't know much about chemistry, I like to include examples from chemistry in my course, and I prefer for the details to be accurate. Here is a typical exam problem:
> When a container of gaseous nitrogen dioxide is heated abov... |
What are some good examples of rate equations? |
What are some good examples of rate equations for a math class? |
A williamson ether synthesis is conducted using vanillin, KOH, EtOH, water, and benzyl chloride.
a) why is the water needed for the synthesis?
b) why must the solution reflux for an hour to gain the desired product?
c) why is water added after reflux to create a cloudy solution? |
Williamson ether synthesis is conducted using vanillin, $\ce{KOH}$, $\ce{EtOH}$, water and benzyl chloride.
1. Why is water needed for the synthesis?
2. Why must the solution be refluxed for an hour to gain the desired product?
3. Why is water added after reflux to create a cloudy solution? |
[Link to question paper][1]
The question says:
> The phase transition from gas to solid is called
(A) condensation. (B) evaporation.
(C) polymerization. (D) sublimation
I am pretty sure the answer is deposition, which is not listed, but yet the answer is (A), condensation [scroll to the end of the question... |
> Changes in which factors affect both the rate and the rate
constant of a first order reaction?
>
I. temperature
>
>II. concentration
>(A) I only (B) II only
(C) Both I and II (D) Neither I nor II
I would think that the answer would be (C), both temperature and concentration.
Concentration would ... |
Changes in which factors affect both the rate and the rate constant of a first order reaction? |
a)
- Consider the phases for potassium hydroxide and benzyl chloride at room temperature.
- Why might you not want to use ethanol as the solvent to form the benzyl alkoxide of vanillin in?
- (As an aside, think about why you might not want to use water over, say, acetonitrile as a solvent for this reaction.)
... |
For example, given a reaction
$\ce{NaCl -> Na+ + Cl-}$
and its $Ksp$ value, I know that you can set up
$$Ksp\; =\; \left[ \ce{Na^{+}} \right]\left[ \ce{Cl^{-}} \right]$$ and solve from there.
My question is why do you not put $\ce{[NaCl]}$ in the denominator, as isn't that part of the equilibrium expression ... |
KOCN + C + heat =? |
Firstly, what geometry does the complex have?
Once you know the geometry, find the spin-state of the $d$-electrons, as well as the number of $d$-electrons applicable.
Find the crystal field diagram relevant to your geometry. Fill in the $d$-electrons according to the aufbau principle and to Pauli's exclusion prin... |
Firstly, what geometry does the complex have?
Once you know the geometry, find the spin-state of the $d$-electrons, as well as the number of $d$-electrons applicable.
Find the crystal field diagram relevant to your geometry. Fill in the $d$-electrons according to the Aufbau principle and to Pauli's exclusion prin... |
My chemistry teacher in high school didn't know the formula for carbonic acid, which struck me as something someone with a degree in chemistry (as they allegedly do) should know instantly, or at least after some time thinking. However, to give them the benefit of the doubt - is carbonic acid a relativly common chemical... |
How well known is the formula of carbonic acid? |
I was trying to isolate elemental bismuth from pepto bismol (bismuth subsalicylate) using the process seen [here](http://www.youtube.com/watch?v=Hp1fYtYEfoQ) but after I added the HCl, instead of getting a pink foamy substance I got a white liquid with some white foam. The only reason I can think of, for why this would... |
Considering this diatomic molecule, the total wavefunction $\Psi$ is formed via a linear combination of the atomic orbitals $\psi_1$ and $\psi_2$ (which is an approximation, but not a too bad one).
$$ \Psi^+ = c_1 \psi_1 + c_2 \psi_2 $$
$$ \Psi^- = c_1 \psi_1 - c_2 \psi_2 $$
The (electronic) energy of the system c... |
I just learned about rate and order... I just want to confirm if these three ideas are correct:
1. If the first elementary step is the slow step, will the stoichiometric coefficients of the reactants in the rate determining step (RDS) be EQUAL to the order the concentration of the reactants in the rate equation is r... |
My chemistry teacher in high school didn't know the formula for carbonic acid, which struck me as something someone with a degree in chemistry (as they allegedly do) should know instantly, or at least after some time thinking. However, to give them the benefit of the doubt - is carbonic acid a relativly common chemical... |
Why is phenolphthalein an appropriate indicator for titration of a strong acid with a strong base? |
> At the triple point of water how do the entropies of solid,
liquid, and gas compare?
I think that either they will be equal or it will be that gas > liquid > solid.
I don't know if entropy is influenced by the fact that it will be at the triple point. Can someone please elaborate? |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.