Help kp q chem

I don’t understand why when temperature increase leads to an exothermic reaction. Wouldn’t it be endothermic as
Tupendtrex
Temperature up (increase) is endothermic as energy is absorbed as a result of increase in tenperature

(edited 1 year ago)

Reply 1

blue_dalmatian

The easiest way to think of this is to think of how a Kp is set up - Product 1 x Product 2/Reactant 1 x Reactant 2.

As the temperature increases, the table shows that Kp decreases. This suggests that, as you increase the temperature, you’re getting a greater number of moles if the reactants. Therefore, this must mean that equilibrium is being shifted to favour the backwards reaction to decrease the temperature. This must mean that the backwards is endothermic, and your forward reaction is exothermic :smile:

Think of it this way: Reactant —-> Product

At 298K: 4/5 = Kp = 0.8
At 1000K: 4/50 = Kp = 0.08 :smile:

(edited 1 year ago)

Reply 2

Obsidian♡Hart

Ok so basically as the temperature increases the Kp value is decreasing.
Kp = p(NO2)^2 / p(NO)^2 x p(O2)
So if the Kp value is decreasing the amount of product produced in this case NO2 has reduced. This means that the increase in temperature has not favored the forward reaction. Therefore the forward reaction in exothermic.