Partial Pressures and Kp

Partial Pressure-

• In a mixture of gases, each gas contributes to the total pressure.
• The partial pressure of a gas in a mixture is the pressure that the gas would exert if it occupied a container of its own.
• If a mixture of gases contains 3 different gases then the total pressure will equal the 3 partial pressures added together. P= p1+p2+p3
• Partial pressure= mole fraction x total pressure of gas 1

     p1= x1 x P

• Mole fraction= number of moles of a gas

                            Total number of moles of all gases

• Writing an expression for Kp

N2 + 3H2 -> 2NH3

Kp= p2 NH3

      pN2 P3 H2

Effect of changing conditions on value of Kc or Kp

• The larger the Kc the greater the amount of products.
• If Kc is small we say the equilibrium favours the reactants.
• Kc and Kp only change with temperature. It does not…