Guys, i need your help for the following questions:


2. consider the following rxn:

2H2 (g) + O2 (g) ------> 2H2O (g)

which of the following would decrease the proportion of water vapor at equilibrium?

a. increasing the partial pressure of oxygen gas
b. decreasing the volume of the container
c. reducing the amount of catalyst present
d. raising the temp

ans. is D but it just does not make sense. well, both A and B would shift the rxn to right and we want to shift the rxn to left so we can eliminate that. next , reducing amn of cat. would shift to left and choice D, raising temp would just shift the rxn to right, so i would go with c but the ans. is D. why?

3. which of the following conditions are required in order for a negative delta G to indicate a spontanious reaction?

I. constant pressure
II. constant temp
III. constant vol.

a. I
b. II only
c. I and II
d. I, II, III
ans is C but why. for sure we know about constant temp so A is out now is entropy related to constant volume. i would say if there is dissociation between molecules then we would have more volume of it so i would include III and i picked D but C is the ans. how come?

4. a particular endothermic rxn causes a decrease in the entropy of the system. this reaction:

a. can never occur since it decreases system entropy
b. can never occur since the free energy change will be positive
c. can only occur at low temp where entropy is a smaller factor
d. can occur if coupled to another reaction

ans. is D why?

I don't see any difference between your 1st and 3rd question. Am I really that tired :(

i think for the 1, its all of em. its ab, or abc..

Guys, i need your help for the following questions:

1.which of the following conditions are required in order for a negative delta G to indicate a spontaneous reaction?

a. constant pressure
b. constant temp
c. constant vol

1. a
2. b
3. a,b
4. a,b,c

2. consider the following rxn:

2H2 (g) + O2 (g) ------> 2H2O (g)

which of the following would decrease the proportion of water vapor at equilibrium?

a. increasing the partial pressure of oxygen gas
b. decreasing the volume of the container
c. reducing the amount of catalyst present
d. raising the temp

ans. is D but it just does not make sense. well, both A and B would shift the rxn to right and we want to shift the rxn to left so we can eliminate that. next , reducing amn of cat. would shift to left and choice D, raising temp would just shift the rxn to right, so i would go with c but the ans. is D. why?

3. which of the following conditions are required in order for a negative delta G to indicate a spontanious reaction?

I. constant pressure
II. constant temp
III. constant vol.

a. I
b. II only
c. I and II
d. I, II, III
ans is C but why. for sure we know about constant temp so A is out now is entropy related to constant volume. i would say if there is dissociation between molecules then we would have more volume of it so i would include III and i picked D but C is the ans. how come?

My understanding to these question might be really wrong. But when you look at it this way. Spontaneous reaction defined as it occur on it own, without any help. Changing pressure or temperature will help the reaction going in particular reaction, for instance.
For number 2, it does not make any sense since at equilibrium, increasing temperature always rising the gas water vapor. I hope that the answer is wrong. If not, i am screwed because it is just whack

For number1 or 3, If we use delta G = delta H - Tdelta S, I think volume can't be constant becuz that will make delta S = 0 and that's when it's at equilibrium, not spon.
That's why volume and temperature should remain constant.

But if volume stays the same but state of the matter changes gas-solid-liquid, then maybe it's possible, but is it possible to change the state without changing the volume?