Question

Predict the effect of the following changes on the reaction in which SO3 decomposes to form SO2 and O2. 2 SO3(g)  2 SO2 (g) + O2 (g) Ho = 197.78 kJ

(a) Increasing the temperature of the reaction.

(b) Increasing the pressure on the reaction.

(c) Adding more O2 when the reaction is at equilibrium.

(d) Removing O2 from the system when the reaction is at equilibrium.

(e) Adding N2 gas to the reaction mixture

Answer 1

Reaction is

2 SO3(g) --- >  2 SO2 (g) + O2 (g)   DeltaH = 197.78 kJ

To answer all of sub question we use Le Chatelier’s principle.

The principle : If any equilibrium is disturbed by any mean it tries again to re establish by making changes in the reaction. The changes many be number of moles , Temperature , pressure , etc.

a). Increasing Temperature :

Given reaction is endothermic since its Delta H has positive value. When we increase the temperature the reaction favors to the right side or forward direction.

b).

If we increase the pressure then reaction goes to the less number of moles of gases in the reaction.

In given reaction number of moles of gas are less to the left side so reaction would prefer to go the left side.

c) At equilibrium when we add more O2 then reaction goes to reverse direction in order to avoid excess O2 than required for stoichiometric limit.

d)

If we remove O2 then reaction goes to the right side in order to make more O2 to reestablish an equilibrium.

e)

If we add N2 gas then there is no any effect on the reaction since N2 in not reactive.