Page 60 - 6273

Le Chatelier’s principle: if one of the conditions under which the system is in

equilibrium (temperature, pressure, or concentration) is changed, then the

equilibrium shifts in the direction of the reaction that counteracts this change.

Examples of sum solving

Example 1. Write the kinetic equation of speed for a direct reaction:

а) N 2(gas) + 3Н 2(gas) = 2NН 3(gas)

b) CaCO 3 (solid) → СаО(solid) + СО 2(gas)

Solution:
3
а) υ . = k[N 2]·[H 2] ;

b) since calcium carbonate is a solid and its concentration in the process of
reaction does not change, the expression of the velocity equation will have the

form:
υ = k

that is, the speed of this reaction at a certain temperature is a constant value.
Example 2. How does the speed of the direct reaction change?

2СО(gas) + О 2(gas) = 2СО 2(gas),

if the volume of the reaction occurs is doubled?

Solution:

According to the kinetic equation, the velocity υ of the direct reaction before the

volume is changed:

2
υ . = k [CO] [О 2]

60