Kc problems

Equibrium WS
Name_______________________________________________
1.Write the equilibrium constant expression for the following reactions:
3 Fe(s) + 4 H2O (l)  Fe3O4 (s) + 4 H2 (g)
2 NOCl (g)  2 NO (g) + Cl2 (g)
2 CO2 (g) + H2O (l)  2 O2 (g) + CH2CO (g)
CH4 (g) + 2 O2 (g)  CO2 (g) + 2 H2O (g)
2. At equilibrium at 100oC, a 2.0L flask contains:
0.075 mol of PCl5
0.050 mol of H2O
0.750 mol of HCl
0.500 mol of POCl3
Calculate the Keq for the reaction: PCl5 (s) + H2O (g) ⇄ 2HCl (g) + POCl3 (g)
3. Keq= 798 at 25oC for the reaction: 2SO2 (g) + O2 (g) ⇄ 2SO3 (g).
In a particular mixture at equilibrium, [SO2]= 4.20 M and [SO3]=11.0M. Calculate the equilibrium [O2] in this
mixture at 25oC.
4. Consider the following equilibrium: 2SO2 (g) + O2 (g) ⇄ 2SO3 (g)
0.600 moles of SO2 and 0.600 moles of O2 are present in a 4.00 L flask at equilibrium at 100oC. If the Keq = 680.0,
calculate the SO3 concentration at 100oC.
5. a. At a certain temperature, Kc is 4.13 x 10-2 for the equilibrium: 2 IBr (g)  I2 (g) + Br2 (g)
What are the concentrations of I2 (g) and Br2 (g) in equilibrium with 0.0124 moles/liter of IBr(g) ?
6. The equilibrium constant is 2.60 x 10-3 for the reaction at 1100 °C:
2 NO (g)  N2 (g) + O2 (g)
If 0.820 mole of NO (g) and 0.223 mole each of N2 (g) and O2 (g) are mixed in a 1.00 liter container at 1100 °C,
what are the concentrations of NO (g), N2(g), and O2 (g) at equilibrium?
7. For the equilibrium: Br2 (g) + Cl2 (g)  2 BrCl (g)
at 205 °C, the equilibrium constant, Kc, is 6.99. If 1.34 moles each of Br2 (g) and Cl2 (g) are introduced
in a container which has a volume of 11.0 liters and allowed to reach equilibrium what would be the
concentrations of Br2 (g), Cl2 (g), and BrCl (g) at equilibrium?
8. For the equilibrium: N2 (g) + O2 (g)  2 NO (g)
at 300 K, the equilibrium constant, Kc, is 5.41. If 1.45 moles each of N2 (g) and O2 (g) are introduced in
a container that has a volume of 6.00 liters and allowed to reach equilibrium at 300 K, what are the
concentrations of N2 (g ), O2(g),and NO (g) at equilibrium?
9 . A mixture of 3.31 moles of A, 4.33 moles of B, and 5.95 moles of C is placed in a one-liter
container at a certain temperature. The reaction was allowed to reach equilibrium. At equilibrium, the
number of moles of B is 6.16 . Calculate the equilibrium constant, Kc, for the reaction:
A (g)  3 B (g) + 2 C g)