LeChatelier's principle and heat

[Maverick56]

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The correct answer is A.

Okay, so I am confused on this one. Since the reaction is exothermic, I placed heat on the products side. Wouldn't adding heat (increasing the temperature) shift the reaction to the left, answer B?

This might be me misunderstanding rate vs. equilibrium??

The solutions states, "rates always increase when temp is increased, even when the reaction is exothermic."

 

[SKaminski]

Please note, the chem section is the last section for me to study, so i may be slightly rusty on this.

The question is asking SPECIFICALLY about the the forward reaction rate. It's not asking about equilibrium, it's not asking about net reaction direction. It is strictly asking about the forward reaction rate.

And, as the solution states: Rates always increase when temp is increased.

You took the thinking a step further and applied the increase of temperature to both sides of the equation. You're correct in doing this, but the question isn't testing this.

Does that make sense?

 

[image187]

True that. Regardless of where the equilibrium lies, increasing the temperature of the system will cause it to reach equilibrium faster. And I don't actually think increasing the temperature would shift the equilibrium away from the right since the energy would be added to both sides of the equation equally, but i could be totally wrong about this so correct me if i am

 

[LoLCareerGoals]

This is a kinetics question:
Equilibrium is related to kinetics via: Keq = kf/kr
kf = Const*e^(-Eactivation/RT). Bigger T -> less neg the exponent -> bigger e^(exp) -> bigger net kf.
Do not equate heat to temp.

 

[justhanging]

This is a typical confusion, you gotta separate thermodynamics from kinetics.

 

[Gauss44]

The correct answer is A.

Okay, so I am confused on this one. Since the reaction is exothermic, I placed heat on the products side. Wouldn't adding heat (increasing the temperature) shift the reaction to the left, answer B?

This might be me misunderstanding rate vs. equilibrium??

The solutions states, "rates always increase when temp is increased, even when the reaction is exothermic."

Reverse reaction rate increases more than forward reaction rate. They both increase.

The author of that problem should have made an equilibrium arrow instead of the arrow shown. The arrow shown make it look like a one-way reaction.