collision theory
TRANSCRIPT
What is collision theory? A theory used to explain chemical reactions in terms
of:
I. Collisions between particles
II. Effective collisions
III. Activation energy
The collision theory state: A chemical reaction occurs when the reactant particles
collide with each other for bond breaking & bond formation
Not all collision result in a reaction to form the product
Effective collisions: A collisions which achieved a minimum energy and with the correct orientation
What is activation energy? The minimum amount of energy which a reactant
must have that can result a chemical reaction.
Tenaga minimum yang diperlukan oleh bahan tindak balasyang akan menghasilkan tindak balas
Energy profile diagram
Exothermic reaction Endothermic reaction
Frequency of effective collision The number of effective collisions occuring in one
second
Frequency of effective collision
High
High rate of reaction
Low
Low rate of reaction
Collision Theory and Factors Affecting the
Rate of Reactions
Effect of Total Surface Area When size of reactant smaller, the total surface
area exposed to collision with other reactants is
bigger.
Thus, the frequency of collision increase.
Frequency of effective collision increase.
Hence, rate of reaction high.
Effect of Total Surface Area When size of calcium carbonate smaller, the
total surface area exposed to collision with other
reactants is bigger.
Thus, the frequency of collision between hydrogen ions and carbonate ions increase.
Frequency of effective collision between hydrogen ions and carbonate ions increase.
Hence, rate of reaction high.
Effect of Concentration & Pressure When concentration of solution increase, the
number of particles per unit volume of the
reactant increase.
Thus, the frequency of collision increase.
Frequency of effective collision increase.
Hence, rate of reaction high.
Effect of Concentration & Pressure When concentration of sodium thiosulphate
solution increase, the number of thiosulphateions per unit volume increase.
Thus, the frequency of collision between thiosulphate ions and hydrogen ions increase.
Frequency of effective collision between thiosulphate ions and hydrogen ions increase.
Hence, rate of reaction high.
Effect of Temperature When temperature increase, the kinetic energy
of the reactant increase.
Thus, frequency of collision increase.
Frequency of effective collision increase.
Hence, rate of reaction high.
Effect of Temperature When temperature increase, the kinetic energy
of the thiosulphate ion increase.
Thus, frequency of collision between thiosulphate ions and hydrogen ions increase.
Frequency of effective collision between thiosulphate ions and hydrogen ions increase.
Hence, rate of reaction high.
Effect of Catalyst The presence of catalyst allows the reaction to take
place through alternative path which requires a
lower activation energy.
Thus, colliding particles able to achieve the lower activation energy.
Frequency of effective collision increase.
Hence, rate of reaction high.
Effect of Catalyst The presence of copper(II) sulphate lower the
activation energy.
Thus, frequency of collision between zinc atom and hydrogen ions increase.
Frequency of effective collision between zinc atom and hydrogen ions increase.
Hence, rate of reaction high.
Ea
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