Chemical EquilibriumChapter 15

15.8

Write the expressions for the equilibrium constants KP of these thermal decompositions:

2NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(g)

2CaSO4(s) 2CaO(s) + 2SO2(g) + O2(g)

15.14

Consider the following equilibrium process at 700oC:

Analysis shows that there are 2.50 moles of H2, 1.35 x 10-5 mole of S2, and 8.70 moles of H2S present in a 12.0-L flask at equilibrium. Calculate the equilibrium constant Kc for the reaction.

2H2(g) + S2(g) 2H2S(g)

15.32

A sample of pure NO2 gas heated to 1000 K decomposes:

The equilibrium constant KP is 158. Analysis shows that the partial pressure of O2 is 0.25 atm at equilibrium. Calculate the pressure of NO and NO2 in the mixture.

2NO2(g) 2NO(g) + O2(g)

15.48 Consider the equilibrium process:

Predict the direction of the shift in equilibrium when

(a) the temperature is raised, (b) more chlorine gas is added to the reaction mixture, (c) some PCl3 is removed from the mixture, (d) the pressure on the gases is increased, and (e) a catalyst is added to the reaction mixture.

PCl5(g) PCl3(g) + Cl2(g) Ho = 92.5 kJ/mol

15.52 Consider the reaction at equilibrium in a closed container:

What would happen if (a) the volume is increased, (b) some

CaO is added to the mixture, (c) some CaCO3 is removed, (d) some CO2 is added to the mixture, (e) a few drops of an NaOH solution are added to the mixture, (f) a few drops of an HCl solution are added to the mixture (ignore the reaction between CO2 and water), and (g) the temperature is increased.

2CaCO3(s) CaO(s) + CO2(g)

Practice exercise, p. 491

The equilibrium constant (Kc) for the formation of nitrosyl chloride, an orange-yellow compound, from nitric oxide and molecular chlorine

is 6.5 x 104 at 35oC. In a certain experiment, 2.0 x 10-2 mole

of NO, 8.3 x 10-3 mole of Cl2, and 6.8 moles of NOCl are mixed in a 2.0-L flask. In which direction will the system proceed to reach equilibrium?

2NO(g) + Cl2(g) 2NOCl(g)