Question

2 SO2 (g) + O2 (g) = 2 SO3 (g) + Energy Predict the effect of each of the following changes on the number of moles of S03 present in the mixture at equilibrium Decreasing the volume of the system Adding oxygen to the equilibrium mixture Raising the temperature of the system Decreasing the pressure of the system Adding a catalyst 2 SO2 (g) + O2 (g) = 2 SO3 (g) + Energy Predict the effect of each of the following changes on the rate of the forward reaction. Decreasing the volume of the system Adding oxygen to the equilibrium mixture Raising the temperature of the system Decreasing the pressure of the system Adding a catalyst

Answer 1

2SO2 + O2 ----> 2SO3 + Energy

Decreasing the volume - moles of SO3 will increase as decreasing pressure will shift the reaction towards SO3.
Adding oxygen to equilibrium mixture - moles of SO3 will increase as O2 is a reactant, increasing reactant will proceed with the reaction towards the product.
Raising the temperature of the system - being an exothermic reaction increase in temperature will reduce the moles of SO3 produced.
Decreasing the pressure of the system - Decreasing the pressure is accompanied by volume ncrease. Tyhen it will proceed towards the higfher number of moles. So, moles of SO₃ will reduce.
Adding a catalyst - moles of SO3 will not change on the addition of catalyst but equilibrium will be formed earlier.

2SO₂ + O₂ ----> 2SO₃ + Energy

Decreasing the volume - The rate of forwarding reaction will increase as the decreasing volume will shift the reaction towards the lesser number of moles, thus SO₃ production will be higher.
Adding oxygen to equilibrium mixture - It is one of the reactants, so adding O₂ will increase the rate of the forward reaction.
Raising the temperature of the system - As it is an exothermic reaction, adding temperature will decrease the forward rate of reaction.
Decreasing the pressure of the system - Decreasing pressure is accompanied by inceasein volume, so it will proceed towards the higher number of moles. So rate of forward reaction will reduce and backward reaction will rise.
Adding a catalyst - Adding a catalyst will increase the rate of forward reaction as well as the backward reaction.