RATE OF REACTION

WEEK THREE
DATE: _________
TOPIC: RATE OF REACTION
CONTENT
 Meaning of Rate of Chemical Reaction.
 Rate Curve.
 The Collision Theory.
 Factors Affecting Rate of Chemical Reactions
MEANING OF RATE OF REACTION
Chemical reactions are changes in which some new
chemical substances are formed.
The rate of a chemical reaction is the number of moles of
reactants converted or products formed per unit time.

Usually, rate of reaction is determined experimentally by
measuring change in concentration of one of the
components in the reaction with time.

Thus,
Rate of reaction = change in concentration of reactant or
product (mol/dm3)
Time taken for the
change (seconds)
The unit of the rate of reaction is mol/dm-3s-1 or g dm-3s –1.
Rate of reaction can also be expressed as:
Rate of reaction = change in number of mole or mass of
reactant or product
Time taken for the
change
Then the unit of rate is mols-1 or gs-1

EXAMPLE: When 0.5g of calcium trioxocarbonate (IV)
was added to excess dilute hydrochloric acid, carbon (IV)

, oxide was evolved. The complete reaction took 5
minutes. What was the rate of reaction?
SOLUTION:
Rate of reaction = change in mass of reactant
Time taken for the change
= (0.5 – 0)g = 0.5
5x60 300
= 1.67 x 10 gs-1
-3