Summary

The further study of equilibria considers how the mathematical expression for the equilibrium constant Kp enables us to calculate how an equilibrium yield will be influenced by the partial pressures of reactants and products. This has important consequences for many industrial processes.

Specification

3.1.10 Equilibrium constant Kp for homogeneous systems

The equilibrium constant Kp is deduced from the equation for a reversible reaction occurring in the gas phase.

Kp is the equilibrium constant calculated from partial pressures for a system at constant temperature.

Students should be able to:

• derive partial pressure from mole fraction and total pressure

• construct an expression for Kp for a homogeneous system in equilibrium

• perform calculations involving Kp

• predict the qualitative effects of changes in temperature and pressure on the position of equilibrium

• predict the qualitative effects of changes in temperature on the value of Kp

• understand that, whilst a catalyst can affect the rate of attainment of an equilibrium, it does not affect the value of the equilibrium constant.

Notes