Achieve Week 1 Assignment: Question #7

[Sasha Gladkikh 2A]

Why is the reaction quotient (Q) not affected by temperature change, in contrast to the equilibrium constant (K) which is affected?

[zackdouchy]

The reaction quotient is not affected by temperature change because its simply a value that assesses the state of the dynamical equilibrium system.

[Austin_Schwartz_1L]

Hello,
There is no change in concentrations following a temperature change, which means the reaction quotient (Q) will not change.
I hope this helps!

[Aliza Hacking 1A]

Hi! So K is a value that will be the same for a given reaction regardless of starting concentrations, but that value changes depending on temperature. Q, by contrast, is a changing value that will differ depending on the starting concentrations and how much time has passed. Though suddenly changing the temperature could alter the concentrations which would alter Q, since Q itself is not a constant but is a calculated value based on present concentrations, temperature would not directly affect Q until it caused a change in the concentrations that Q is calculated based on.

[Raizel Ferrer 1H]

The equilibrium constant, K, is affected by temperature change because this affects the production of reactants or products due to the additional heat used. Q is the reaction quotient and is used at any time during the reaction to compare to K. Q usually depends on the concentrations at the time of a reaction rather than K which depends on only the initial molar concentrations.

[Daniela G 2C]

Q is used as a way to determine the direction of a reaction at any time using the concentrations at a given time. In the problem, no concentrations were added, subtracted, or changed due to temperature, thus Q does not change.

[Lawrence Tran 2H]

Q is only concerned with the reactant/product concentrations at any moment, so it's not affected by temperature. Meanwhile K is concerned with the concentrations at equilibrium, which IS affected by temperature,

[Jenny Han 3F]

The other replies are great! Another way of looking at it (though we haven't learned this in class yet I believe) is with the Gibbs free energy equation ΔG = -RTln(K), where ΔG is the change in Gibbs free energy, R is the universal gas constant, T is temperature, and K is the equilibrium constant. The Gibbs free energy measures the max amount of work/energy done in done in a system and would be equal (but opposite signs from opposite directions) in the forward and reverse reaction at equilibrium. Thus, the G forwards and backwards cancel out; ΔG equals 0 at equilibrium and R is constant, so a change in T would initiate a change in K.