- Physical Chemistry I
Spring 2012, Unique 52135
Homework, Week 10
1. Determine DG0rxn and KP at 298 K for each of the following reactions:
a) N2O4(g) « 2 NO2(g)
b) H2(g) + I2(g) « 2 HI(g)
c) 3 H2(g) + N2(g) « 2 NH3(g)
of ammonia is given by the formula
N2(g) + 3 H2(g) « 2 NH3(g)
a) If you begin the reaction with n0 moles of N2(g) and 3n0 moles of H2(g), find an exact expression for zeq. Use this expression to discuss how zeq varies with P and relate your conclusions to Le Chatelier’s principle.
3. Sufuryl chloride, SO2Cl2, decomposes to sulfur dioxide and chlorine gas:
SO2Cl2(g) « SO2(g) + Cl2(g)
DG0f (SOCl2) = -371.3 kJ/mol, DG0f (SO2) = -300.2 kJ/mol.
a) Determine the equilibrium concentrations of each species if the system initially contains 1 mole of SO2Cl2 and 0 moles of SO2 and Cl2 at 1 bar
b) Determine the equilibrium concentrations of each species if the system initially contains 1 mole of SO2Cl2, 1 mole of SO2, and 0 moles of Cl2 at 1 bar.
c) Describe any differences according to Le Chatelier’s principle.
4. The water-gas shift reaction is an important industrial source of pure H2(g) for ammonia synthesis:
CO(g) + H2O(g) « H2(g) + CO2(g)
What would happen to the equilibrium concentration of each species if you increase the total pressure of the system by a factor of 100?
values of KP
were reported assuming a standard state of 1 atm. Determine a general equation for converting KP
values at 1 atm to 1 bar.
6. Under certain conditions, water vapor dissociates into H2(g) and O2(g). At 2000 K and 1 bar, water vapor is 0.53% dissociated. At 2100 K and 1 bar, it is 0.88% dissociated. Determine the enthalpy of the dissociation reaction, assuming it is constant over this temperature range.