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Chemical Equilibria 209
Given the following equilibrium (endothermic as written), predict what changes,
if any, would occur if the following stresses are applied after equilibrium was
established?
a. Add CO2 b. Remove CO2 c. Add CaO
d. Increase T
e. Decrease V
f. Add a catalyst
CaCO 3(s) K CaO(s) CO 2(g)
Answers:
a. Left—the equilibrium shifts to remove some of the excess CO2. b. Right—the equilibrium shifts to replace some of the CO2. c. No Change—solids do not shift equilibria unless they are totally removed.
d. Right—endothermic reactions shift to the right when heated.
e. Left—a decrease is volume, or an increase in pressure, will shift the equilibrium
towards the side with less gas.
f. No Change—catalysts do not affect the position of an equilibrium.
14-4 Utterly Confused About
Equilibria Problems
Don’t Forget!
Equilibria problems require an equilibrium constant expression in nearly every
case. You should begin each problem with this expression. This will get you
started on the problem.
Let’s do a series of equilibria problems. You should pay close attention not only
to what is different about each problem, but also to what is the same.