Summary Kp Notes - AQA Chemistry A Level

Kp
Partial Pressure
 Each individual gas in a mixture of gases exerts its own pressure – ‘partial pressure’
 The total pressure of a gas mixture is the sum of all the partial pressures of the individual gases
 Mole fraction of gas x total pressure of mixture

Mole Fraction
 The proportion of a gas mixture that is made up of a particular gas
 Sum of all mole fractions is 1




Gas Equilibrium Constant (Kp)
 aA + bB ⇌ cC + dD



 Partial pressures are used in kPa
 Units of Kp depend on the values of a, b, c and d but are multiples of kPa
 Kp is only affected by changes in the temperature – equilibrium position shifts in endothermic
direction for raising temperature and exothermic direction for lowering temperature