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Chemical KineticsAGIndexMeaning of Chemical KineticsRate of
chemical reactionFactors affecting rate of reactionOrder and
MolecularityRate law expressionAGWhat is Chemical Kinetics?
Why we are studying it?
AGWhatBranch of science dealing with rate of chemical reactions
and their mechanisms
WhyScientists and Engineers require this knowledge so as to set
up their apparatus accordingly and make it more economical by
increasing or decreasing the speed of reactions. Automobile
accelerator example.31.1 Types of reactions based on speedVery fast
reactionsModerate speed reactionsVery slow reactions
AGMolecular reactions
AGIndexMeaning of Chemical KineticsRate of chemical
reactionFactors affecting rate of reactionOrder and
MolecularityRate law expressionAGRate of chemical reaction (1/2)2.1
Standard Definition
2.2 Understanding RoR through Collision theoryBAAAAABBBBABAG
Rate of chemical reaction (2/2)2.3 Unit of Rate of reactiona.
Concentration
b. Pressure
2.4 Importance of stoichiometry BAAAAABBBB2AABAG2.5 There are
two types of ratesAverage rate
Instantaneous rateAGExamples (1/4): Meaning of differentials1.
Concentration of reactant in a chemical reaction decreases with
time according to the given equation c=2-3t-5t2 . Calculate initial
rate and rate at time t=2s.AGExamples (2/4): Reaction
Stoichiometry2H2O2 2H2O + O2
N2 + 3H2 2NH3
2SO2 + O2 2SO3
1/2 A + 1/3 B 1/5 C AGExamples (3/4): Volumetric titrationAG
t = 0 [A]=10Mt = 10 [A]=5M
Volumetric titration for A in the reaction sample at T = 10
min6. If reaction is 2A + 3B 5C at T=320K, then give rA, rB and
rABExamples (4/4): Gaseous Phase reaction 7. For a gaseous phase
reaction at 300K, A(g) B(g), if pressure of A decreases by 2 atm to
1.5 atm in 10 min, calculate rate of chemical reaction in terms
of:a. pressure/timeb. conc./timeAGIndexMeaning of Chemical
KineticsRate of chemical reactionFactors affecting rate of
reactionOrder and MolecularityRate law expressionAG3.1 Three major
factors affecting rate of reactionConcentrationTemperatureEffect of
catalystPressure of container (for gaseous reactions)Radiations
(for photochemical reactions)Dielectric constant of mediumElectric
and Magnetic fieldAGVisualizing two cases of concentration
dependency on elementary
reactionAAABBBBABBBBBAAAAAAAAAABBBBABBBBBAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGCase
I: Equal and low concentration of both reactantsCase II: One of the
reactant is in excess and another is limitingRate Law
ExpressionRate Law Expression
Order with respect to reactants
Order for the reaction
Properties of kAGExamples of order2O3 3O2 ; R = k[O3]2[O2]-1
CH3CHO CH4 +O2 ; R = k[CH3CHO]1.5AGElementary vs Complex
reactions: The experimental truth (1/2)MolecularityElementary
StepExampleUnimolecularAProductsN2O4(g)2NO2(g)BimolecularA+BProductsCO(g)+NO3(g)NO2(g)+CO2(g)TermolecularA+A+BProducts2NO(g)+O2(g)2NO2(g)AGElementary
vs Complex reactions: The experimental truth (2/2)AG(CH3)3C-Br +
CH3CH2OH (CH3)2C=CH2 +CH3CH2OH2+ + Br-
MolecularityAGAG
