This document discusses factors that affect the rate of a chemical reaction. It defines the rate of reaction as the change in amount of reactant or product over time. The rate of reaction is affected by several factors, including the concentration of reactants, temperature, surface area, and presence of catalysts. A faster rate of reaction occurs when these factors increase the frequency of effective collisions between reactant particles that possess sufficient energy to overcome the activation energy barrier.

1. RATE OF REACTION
Prepared by:
Cik Nur Harlyana Binti Harun
SMK Abdul Rahman Talib,
Kuantan.

2. CHEMISTRY……
• The changes involved are
 Physical changes
 chemical changes
Example: crumpling a sheet of paper, melting an
ice cube, breaking a glass, casting silver in the
mold,
Example: burning wood, dissolving salt in water,
mixing acid and base, digestion of food, put
bleach in the washing machine to clean the
clothes, rusting.

3. PHYSICAL CHANGES….

4. PHYSICAL CHANGES….

5. CHEMICAL CHANGES….

6. CHEMICAL CHANGES….

7. CHEMICAL CHANGES….

8. CHEMISTRY……
• Physical change
 no chemical reaction occur
 no new compounds are produce BUT…
 may change in shape/form during the physical
changes.
• Chemical change
 chemical reaction occur
 the reaction produce new substances

9. CHEMICAL CHANGES….
• Chemical reaction involves
 Reactants and products
• Chemical reaction occur at different rate
High rate of reaction>>>fast reaction (in short
period of time)
Low rate of reaction>>>slow reaction (in long
period of time)
Ions ,
compound,
molecules
include
Example:
A → B + C
A + B → C
A + B → C + D + E

10. CHEMICAL CHANGES
Changes in
chemical reaction
Product Temperature
Gas released
Formation of
precipitation
Colour pH
Concentration

11. RATE OF REACTION….
• Generally,
Rate of reaction is the speed at which reaction occur
(reactants react to form products)
• Definition
Rate of reaction is the change of amount of
reactant/product per unit time
Rate of reaction =
𝑐ℎ𝑎𝑛𝑔𝑒 𝑜𝑓 𝑎𝑚𝑜𝑢𝑛𝑡 𝑜𝑓 𝑟𝑒𝑎𝑐𝑡𝑎𝑛𝑡/𝑝𝑟𝑜𝑑𝑢𝑐𝑡
𝑡𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛
• Rate of reaction is inversely proportional to time
taken.
Rate of reaction ∝
1
𝑡𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛

12. MEASURING THE RATE OF REACTION….

13. MEASURING THE RATE OF REACTION….
Method of gas collection by using DOWNWARDS WATER DISPLACEMENT

14. MEASURING THE RATE OF REACTION….

15. MEASURING THE RATE OF REACTION….
Mix :
HCl + Na2S2O3
Ongoing Watch
stopped
Concentration of solution (reactant)/
temperature

16. MEASURING THE RATE OF REACTION….
• Average rate over a period
of time
• The rate of reaction at any
given time
Expressing
rate of
chemical
reaction

17. RATE OF REACTION….
• Factors that affecting the rate of chemical
reaction
The size of the solid particles (total surface area
effect) √
The solution concentration √
The temperature of the reactants √
The presence of catalyst √
Pressure

18. APPLICATION OF THE FACTORS AFFECTING
THE RATE OF REACTION IN DAILY LIFE….
• Burning of charcoal
When smaller pieces of charcoal are used, food can be
cooked faster.
Smaller pieces of charcoal have bigger total
surface area which will burn faster to produce more
heat.

19. APPLICATION OF THE FACTORS AFFECTING
THE RATE OF REACTION IN DAILY LIFE….
• Storing food in a
refrigerator
The low temperature in
the refrigerator will slow
down the rate of decay of
food by microorganism
Hence, the food last
longer.

20. APPLICATION OF THE FACTORS AFFECTING
THE RATE OF REACTION IN DAILY LIFE….
• Cooking solid food in different sizes
Small pieces of food have a larger total surface area
expose to heat.
Thus, they can cooked faster.

21. APPLICATION OF THE FACTORS AFFECTING
THE RATE OF REACTION IN DAILY LIFE….
• Cooking of food in
a pressure cooker
High pressure in a
pressure cooker will
raise the boiling point
of water.
Thus, cooking is
done at a much
higher temperature
than 100 °C and the
food can be cooked
faster.

22. APPLICATION OF THE FACTORS AFFECTING
THE RATE OF REACTION IN DAILY LIFE….
• Industrial process
Catalyst are usually used to increase the rate of
industrial processes.
These enable the processes to be completed in a
shorter time at low temperature and pressure.
Hence, the cost of production will be reduced.
Industry Catalyst
Haber process – manufacture
ammoni, NH3
Iron powder (Fe)
Contact process - manufacture
sulphuric acid, H2SO4
Vanadium(v) oxide, V2O5
Ostwald process - manufacture nitric
acid, HNO3
Platinum (Pt)

23. COLLISION THEORY….
• The collision theory states that for a reaction to
occur between two particles
The reacting particles must collide with each other
The reacting particles must collide with a certain
minimum energy known as the activation energy,
Ea.
The reacting particles collide in the correct
orientation.
• A collision that results in a reaction is called
effective collision.
• If the frequency of effective collision is high, the
rate of reaction is also high.

24. COLLISION THEORY….
• Activation energy, Ea
The minimum energy needed to breaks the bond to
initiate the reaction

25. COLLISION THEORY….
• Activation energy, Ea
The minimum energy needed to forms new bond in
the reaction product.

26. COLLISION THEORY….
• The concentration of reactant
When the concentration of the solution of a reactant
increases, the number of particles per unit
volume of the solution of the reactant also increases.
REACTION: SLOWER
ROR : LOW
REACTION: FASTER
ROR: HIGH

27. COLLISION THEORY….
• The temperature of reaction mixture
When the temperature of reaction increase, the
reacting particles move faster because they have high
kinetic energy.
REACTION: SLOWER
ROR : LOW
REACTION: FASTER
ROR: HIGH

28. COLLISION THEORY….
• The size of reactant
When the size of reactants (with the fixed mass)
becomes smaller, the total surface area exposed to
collision with other particles increases.
REACTION: SLOWER
ROR : LOW
REACTION: FASTER
ROR: HIGH

29. COLLISION THEORY….
• Use of catalyst
When a catalyst is used in a chemical reaction, it
enables the reaction to occur through an
alternative path which requires a lower
activation energy.
REACTION: SLOWER
ROR : LOW
REACTION: FASTER
ROR: HIGH