Le Chatelier’s Principle

Suppose the following exothermic reaction is allowed to reach equilibrium.

A (g) + 3 B (g) ⇌ 2 C (g) + 3 D (g)  ∆H > 0

The following stresses were exerted on the above equilibrium. Describe the shift that will occur to the equilibrium (towards reactants or towards products) and the reason for the shift.

Stress	Shift	Reason	
The temperature is increased while the volume is kept
constant			
more A is added			
a small amount of D is removed			
more C is added			
the pressure is increased
by decreasing the volume			
a catalyst is added			

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Time

In the space below sketch the changes in concentration for each of the species present in the above equilibrium.
Suppose the following exothermic reaction is allowed to reach equilibrium.

2 BrF5 (g) ⇌ Br2 (g) + 5 F2 (g)  ∆H < 0

The following stresses were exerted on the above equilibrium. Describe the shift that will occur to the equilibrium (towards reactants or towards products) and the reason for the shift.

Stress	Shift	Reason	
the temperature is increased while the volume is kept
Constant			
more BF5 is added			
a small amount of Br2 is removed			
more F2 is added			
the pressure is increased
by decreasing the volume			
a catalyst is added			

[ ]

Time

In the space below sketch the changes in concentration for each of the species present in the above equilibrium.