Question
Consider this system at equilibrium.
A(aq) <-> B(aq) Delta H = +750 kJ/mol ..
What can be said about Q and K immediately after an increase in temperature?
a] Q > K because Q increased..
b] Q>K because K decreased..
c] Q<K because Q decreased..
d] Q<K because K increased..
e] Q=K because neither changed
How will the system respond to the temperature increase?
a] shift to the left
b] shift to the right
c] no change
I said that it would shift to the left for the second part [i think] but for the first part i'm not sure because my notes says that adding temperature would cause the reactant concentrations to increase; thus, equilibrium constant K will decrease.
doesn't that mean that a AND b are both correct..? but there can only be one answer from part 1.. please help me reason!
A(aq) <-> B(aq) Delta H = +750 kJ/mol ..
What can be said about Q and K immediately after an increase in temperature?
a] Q > K because Q increased..
b] Q>K because K decreased..
c] Q<K because Q decreased..
d] Q<K because K increased..
e] Q=K because neither changed
How will the system respond to the temperature increase?
a] shift to the left
b] shift to the right
c] no change
I said that it would shift to the left for the second part [i think] but for the first part i'm not sure because my notes says that adding temperature would cause the reactant concentrations to increase; thus, equilibrium constant K will decrease.
doesn't that mean that a AND b are both correct..? but there can only be one answer from part 1.. please help me reason!
Answers
Tracy
and for the sake of understanding.. can someone tell me what would happen if the reaction was exothermic instead of endothermic?
DrBob222
A + heat ==> B
K or Q = (B)/(A)
I may not have interpreted this correctly because I'm not positive a delta T could make an IMMEDIATE impact; however, if we look at the long term, it MUST shift to the right because it's an endothermic reaction and heat is being added. So in the long term B will go up, A will go down, which means K will get larger. Therefore, in the short term Q is too small so Q < what K will be.
The reasoning is the reverse for an exothermic. reaction.
K or Q = (B)/(A)
I may not have interpreted this correctly because I'm not positive a delta T could make an IMMEDIATE impact; however, if we look at the long term, it MUST shift to the right because it's an endothermic reaction and heat is being added. So in the long term B will go up, A will go down, which means K will get larger. Therefore, in the short term Q is too small so Q < what K will be.
The reasoning is the reverse for an exothermic. reaction.
Tracy
thank you Dr. Bob!