EQUILIBRIUM EXPRESSIONS PROBLEMS
Name___________________________per__
Part A. Review of reaction rates:
1. For the reaction 2NO(g) + Cl2(g)  2NOCl(g)
You start with 0.00640mol/L of Chlorine gas but after 60 seconds it has decreased to 0.00295mol/L. What
is the reaction rate?
2. For the reaction Br2(aq) + HCOOH(aq)  2HBr(aq) + CO2(g)
Time
[Br2]
[HCOOH]
[HBr]
0
0.120M
0.120M
0.0
150sec 0.00710M 0.00710M 0.00980M
What is the reaction rate for the disappearance of Br2 over 150 seconds?
3. Use the info in problem 2 to calculate the rate of HBr formation.
PART B. WRITE THE EQUILIBRIUM CONSTANT EXPRESSION FOR EACH REACTION BELOW
4.
N2(g) + 3H2(g)  2NH3(g)
5.
2CO(g) + O2(g)   2CO2(g)
6.
2SO3(g) + CO2(g)   CS2(g) + 4O2(g)
PART C. CALCULATE THE EQUILIBRIUM CONSTANTS FOR THE FOLLOWING REACTIONS AT EQUILIBRIUM
7.
2SO3(g)   2SO2(g) + O2(g)
[SO3] = 0.0160M
8.
PCl5(g)  
[SO2] = 0.00560M [O2] = 0.00210M
PCl3(g)
+ Cl2(g)
A 6.00-L vessel containing:
0.0222 mol PCl3
0.0189 mol PCl5
0.1044 mol Cl2
PART D. USING THE EQUILIBRIUM CONSTANT TO CALCULATE UNKOWN CONCENTRATIONS
9.
Keq is 1.60 at 933 K for:
[CO2] = 0.320M
H2(g) + CO2(g)   H2O(g) + CO(g)
[H2O] = 0.240M
[CO] = 0.280M
Find [H2].
PART E. SOLIDS AND LIQUIDS ARE NOT INCLUDED IN EQUILIBRIUM CONSTANT EXPRESSIONS AS THEIR
CONCENTRATIONS NEVER CHANGE. (THEIR CONSTANTS ARE ALWAYS IN THE CONSTANT K ALREADY). WRITE THE
EQUILIBRIUM CONSTANT EXPRESSION FOR EACH REACTION BELOW
10.
2KClO3(s)   2KCl(s) + 3O2(g)
11.
Fe3O4(s) + 4H2(g)   3Fe(s) + 4H2O(g)
12.
Li2CO3(s)  2Li+(aq) + CO3-2(aq)
PART F. CALCULATE THE EQILIBRIUM CONSTANTS FOR THE FOLLOWING HETEROGENOUS REACTIONS AT
EQUILIBRIUM (DO NOT INCLUDE NUMBERS FOR LIQUIDS NOR SOLIDS)
13.
H2O(l)   H+(aq) + OH-(aq)
density of H2O= 1gr/ml [H+] = 1 x 10-8M [OH-] = 1 x 10-6 M
14.
Li2CO3(s)   2Li+(aq) + CO3-2(aq)
[Li+] = 0.2M
[CO3-2] = 0.1M