Chemical Equilibrium/LCP/Graph

[Coupe]

Based on a graph of LCP concentrations of reactants/products on the Y-axis and time (minutes) on the X-axis.

What would happen if you only know the KC value which is a number greater than 10, and you want to find out whether the reaction is an exothermic or endothermic reaction, can you tell just by the equation (without the delta H given)?

Like I just wanna know is it possible to find whether the reaction is exothermic or endothermic without knowing the delta H values for a given reaction and only knowing the KC values?

 

[Frank]

Exothermic Reactions

• If Kc decreases with an increase in temperature, the reaction shifts to the left.
• If Kc increases with a decreases in temperature, the reaction to shifts to the right.

Endothermic Reactions

• If Kc increases with an increase in temperature, the reaction to shifts to the right.
• If Kc decreases with a decrease in temperature, the reaction to shifts to the left.

You can determine if it is endothermic or exothermic if you know which side of the equation is dominant.

 

Kc is the equilibrium constant. A large Kc is evidence that the reaction favored the product side. Kc=10 would be an example of a large Kc value. A small Kc is evidence that the reaction favored the reactants. If you have no info about delta H, you can use this and Guyfrank's guide to determine if the reaction was exo or endothermic.