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Kinetics and Reaction Rates - Coggle Diagram
Kinetics and Reaction Rates
chemical kinetics
: in which the rate of a reaction is measured
is the measurement of how quickly reactions occur
Rate laws (sometimes called differential rate laws) or rate equations are mathematical expressions that describe the relationship between
the rate of a chemical reaction and the concentration of its reactants.
aA+bB⟶products
:
rate=k[A]^m[B]^n
The rate constant k and the reaction orders m and n must be determined experimentally by observing how the rate of a reaction changes as the concentrations of the reactants are changed.
A common experimental approach to the determination of rate laws is the method of initial rates. This method involves measuring reaction rates for multiple experimental trials carried out using different initial reactant concentrations.
The
rate of reaction
is the change in the amount of a reactant or product per unit time.
aA⟶bB
general rate of reaction
rate=−(1/a)(ΔA/Δt)=(1/b)(Δ/BΔt)
related by the stoichemistry of the reation
The rates of many reactions depend on the concentrations of the reactants.
the rate of a chemical reaction is a measure of how much reactant is consumed, or how much product is produced, by the reaction in a given amount of time.
Substances that function to increase the rate of a reaction are called catalysts
Chemical Nature of the reacting substances: Reactions that appear similar may have different rates under the same conditions,
depending on the identity of the reactants
Chemical reactions typically occur faster at higher temperatures.
First Order Reactions
[A]t=[A]0e^−kt
where [A]t is the concentration of A at any time t, [A]0 is the initial concentration of A, and k is the first-order rate constant.
the equation can be rearranged to other formats
Second Order Reactions:
rate=k[A]^2
1/[A]t=kt+1/[A]0
Integrated rate law(terms in this equation are the same as the first order)
A plot of 1[A]t versus t for a second-order reaction is a straight line with a slope of k and a y-intercept of 1[A]0.
If the plot is not a straight line, then the reaction is not second order.
For zero-order reactions, the differential rate law is:
rate=k
A zero-order reaction thus exhibits a constant reaction rate, regardless of the concentration of its reactant(s).