Question

Consider the following equation in chemical equilibrium.

C2H4(g) + H2(g) <-> C2H6(g) + 137 kJ

What happens to the amount of ethane (C2H6) when the temperature of the system is increased?
a. The amount of ethane decreases.
c. The amount of ethane increases.
d. The amount of ethane decreases initially and then increases.

Answer 1

What do you think? Consider heat as a product

Answer 2

I don't know, c?

I guessed B, but it wasn't correct. I don't understand any of it.

Answer 3

So the rxn is exothermic. So heat is a product

Answer 4

You're adding more heat so think of it this way the reaction is exothermic so when you add heat in there's too much heat so the reaction will go to the left and decrease the amount of product.

Answer 5

I'm still not understanding what the answer would be then, or how to figure it out.

Answer 6

It's like this:
We are given with the enthalpy right? It's a positive charged number which means this is an exothermic reaction. Because in exothermic reactions the heat is given out so enthalpy change is positive.
Can u understand this part?

Answer 7

I understand that.

Answer 8

When we increase the temperature the equilibrium becomes unstable right ?

Answer 9

Yes. Would it be D, then? Or am I jumping too far ahead? Lol.

Answer 10

I thought it would be A though ! What do u think @Photon336 and @taramgrant0543664

Answer 11

According to Le Chatelier's principle the reaction always tries to minimize the stress developed by external conditions. In this case if we increase the temperature the reaction will try to do something which will decrease the temperature. Since the forward reaction is exothermic, equilibrium will shift toward backwards and hence more products will disintegrate to form reactants thus amount of ethane will decrease.