Rate of a chemical reaction is discussed in these slides.Mainly it has been concentrated on Rate Laws and factors affecting the Rate of Reaction

1. RATE
OF
REACTION
Name:W.M.H.G.T.C.K.Weerakoon
Reg_no:13/AS/134
Index no: EP1801
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2. CONTENT
•Definitions
•Rate Law
•Factors affecting Rate of Reaction
-Concentration
-Pressure
-Temperature
-Catalysts
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3. DEFINITIONS
•Reaction-Transformation of chemical substances
from one to another.
•Rate of Reaction-
The rate of change in the concentration of reactant
or
The rate of change in the concentration of products
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4. •Therefore,
𝑅𝑎𝑡𝑒 𝑜𝑓 𝑅𝑒𝑎𝑐𝑡𝑖𝑜𝑛 =
∆𝐶𝑜𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛
𝑜𝑓 𝑟𝑒𝑎𝑐𝑡𝑎𝑛𝑡𝑠 𝑢𝑠𝑒𝑑
𝑇𝑖𝑚𝑒
or
𝑅𝑎𝑡𝑒 𝑜𝑓 𝑅𝑒𝑎𝑐𝑡𝑖𝑜𝑛 =
∆𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛
𝑜𝑓 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑠 𝑓𝑜𝑟𝑚𝑒𝑑
𝑇𝑖𝑚𝑒
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5. General equation,
𝑎𝐴 + 𝑏𝐵 → 𝑐𝐶 + 𝑑𝐷
According to definitions,
𝑅𝑎𝑡𝑒 = −
1
𝑎
∆ 𝐴
∆𝑇
= −
1
𝑏
∆ 𝐵
∆𝑇
=
1
𝑐
∆ 𝐶
∆𝑇
=
1
𝑑
∆ 𝐷
∆𝑇
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6. e.g.: 𝐶2 𝐻4 + 𝑂2 → 𝐶2 𝐻4 𝑂 + 𝑂2
rate=−
∆ 𝐶2 𝐻4
∆𝑡
= −
∆ 𝑂2
∆𝑡
=
∆ 𝐶2 𝐻4 𝑂
∆𝑡
=
∆ 𝑂2
∆𝑡
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7. Rate Law
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8. •A relationship between Rate of Reaction
and Concentration of Reactants
•Assumption:-reaction in a fixed temperature
𝑎𝐴 + 𝑏𝐵 → 𝑐𝐶 + 𝑑𝐷
rate=𝑘 𝐴 𝑚 𝐵 𝑛
𝑘-Rate constant
𝑚,𝑛-Reaction order
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9. FACTORS AFFECTING
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10. REACTI
ON
RATE
CONCENTRATION TEMPERATURE
PRESSURE
CATALYSTS
• Underling
principle running
is COLISSION
THEORY 10

11. Concentration….
𝑐𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 ∝ 𝑅𝑎𝑡𝑒 𝑜𝑓 𝑅𝑒𝑎𝑐𝑡𝑖𝑜𝑛
• Low concentration
leads few collisions
and low speed in
reaction rate.
• High concentration
leads more collisions
and high speed in
reaction rate 11

12. Temperature….
• Low temperature and low average
kinetic energy, less successful
collisions, low rate of reaction
• High temperature and high
average kinetic energy, high
successful collisions, high rate of
reaction
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13. PRESSURE….
• Specially affects on gases
• High pressure, high molecule
density, high effective
collisions and high rate of
reaction.
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14. CATALYSTS….
•Catalysts-Substances that increase rate of
reaction
•Catalysts lower the activation energy and
then high successful collisions
•If to lower the rate of reactions INHIBITORS
could be used
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15. THANK YOU!!!
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