III. Equilibrium (pg. 2a)
AP Chemistry
1) Given the reaction below at equilibrium, state and explain the effect (increase, decrease or no change) the quantity on
the right hand column, given the operation in the left column below. Each operation is to be considered separately.
2 Cl2 (g) + 2 H2O (g) ↔ 4 HCl (g) + O2 (g)
∆H = + 27 kJ
What type of reaction, in terms of heat, is the above reaction?
Stress
a) increasing volume of container
Shift
Effect
concentration of water
b) increase concentration of chlorine
value of equilibrium constant
c) Increase concentration of chlorine
concentration of HCl
d) increase concentration of oxygen
concentration of water
e) increase concentration of oxygen
concentration of HCl
f) increase concentration of oxygen
value of equilibrium constant
g) decrease volume of container
concentration of chlorine
h) decrease volume of container
concentration of oxygen
i) raising temperature
concentration of water
j) raising temperature
concentration of HCl
k) lower temperature
value of equilibrium constant
l) adding He
concentration of oxygen
m) adding a catalyst
concentration of chlorine
n) lowering temperature
concentration of water
o) adding HCl
amount of heat
p) taking away HCl as it is formed
concentration of oxygen
2) Given the reaction below at equilibrium, state and explain the effect (increase, decrease or no change) the quantity on
the right hand column, given the operation in the left column below. Each operation is to be considered separately.
2 C (s) + O2 (g) ↔ 2 CO (g)
∆H = - 26.41 kJ
What type of reaction, in terms of heat, is the above reaction?
Stress
a) increasing volume of container
Shift
Effect
concentration of oxygen
b) increase concentration of oxygen
concentration of carbon
c) increase concentration of oxygen
concentration of CO
d) decrease volume of container
amount of heat
e) decrease volume of container
value of equilibrium constant
f) raising temperature
value of equilibrium constant
g) raising temperature
concentration of CO
h) raising temperature
concentration of oxygen
i) adding He
concentration of CO
j) adding a catalyst
concentration of carbon
k) lowering the temperature
concentration of CO
l) increase concentration of CO
amount of heat
m) taking away CO as it is formed
concentration of oxygen
3) You are given a box in which PCl5 (g), PCl3 (g) and Cl2 (g) are in equilibrium with each other at 546 K. Assuming
that the decomposition of PCl5 to PCl3 and Cl2 is endothermic, what effect would there be on the concentration of PCl 5 in
the box if each of the following changes were made a) add Cl 2 to the box, b) reduce volume of the box and c) raise the
temperature of the system d) add PCl5 to the reaction e) remove Cl2 as it is formed f) add Ar at constant pressure g) add
Ar at constant volume
4) Consider the following equilibrium: N2O4 (g) ↔ 2 NO2 (g)
∆H = 58.0 kJ
In what direction will the equilibrium shift when each of the following changes is made to the system at
equilibrium: a) add N2O4; b) remove NO2; c) increase the total pressure by adding N2 (g); d) increase the volume; e)
decrease the temperature? f) add Ar at constant pressure g) add Ar at constant volume