GENCHEM

• Chemical equilibrium


  A state in which the rate of the forward reaction equals the rate of the backward reaction. There is no net change in concentrations of reactants and products.
• Types of chemical equilibrium

  • Homogeneous Equilibrium
  • Heterogeneous Equilibrium
• Homogeneous Equilibrium


  • Reactants and products are all in the same phase. Examples: H2(g) + I2(g) ⇌ 2HI(g), N2(g) + O2(g) ⇌ 2NO(g)
• Heterogeneous Equilibrium


  • Reactants and products are present in different phases. Examples: CO2(g) + C(s) ⇌ 2CO(g), CaCO3(s) ⇌ CaO(s) + CO2(g)
• Factors affecting chemical equilibrium

  • Change in concentration
  • Change in pressure
  • Change in temperature
  • Effect of a catalyst
• Change in concentration


  When the concentration of the reactant or product is changed, there is a change in the composition of the mixture in chemical equilibrium.
• Change in pressure


  Change in pressure happens due to the change in the volume. If there is a change in pressure it can affect the gaseous reaction as the total number of gaseous reactants and products are now different.
• Change in temperature


  As temperature increases the equilibrium constant of an exothermic reaction decreases. In an endothermic reaction the equilibrium constant increases with an increase in temperature.
• Effect of a catalyst


  A catalyst does not affect the chemical equilibrium. It only speeds up a reaction.