Question

1. For the reaction: 2NOCl(g) 2NO(g) + Cl2(g), Kc = 1.6 x 10− 5 . What are the equilibrium concentrations of each species if 1.0 mole of NOCl is initially placed in an empty

2.0 L flask? 2. A reaction vessel is charged with hydrogen iodide, which partially decomposes to molecular hydrogen and iodine: 2HI (g) H2(g) + I2(g): When the system comes to equilibrium at 425 °C, PHI = 0.708 atm and 2 2 P P H I = = 0.0960 atm. Calculate Kp for this reaction. Calculate Kc for the same reaction.

3.Consider the reaction CH2O (g) CO (g) + H2 (g) In an experiment, 0.050 mol of CH2O (g) was placed in empty 500. mL vessel. At equilibrium, the concentration of CH2O (g) was found to be 0.066 M. Calculate Kc for the reaction.

Answer 1

1)

concentration of NOCl = 1.0 / 2.0 = 0.50 M

2 NOCl    --------------> 2 NO   +   Cl2

0.50                               0              0

0.50 - 2x                        2x            x

Kc = x (2x)^2 / (0.5 - 2x)^2

1.6 x 10^− 5 = 4 x^3 / (0.5 - 2x)^2

x = 9.74 x 10^-3

concentration of species :

[NO] = 0.0195 M

[Cl2] = 0.00974 M

[NOCl] = 0.481 M