Exam 3 Flashcards
The change in concentration of a reactant or product per unit time
Reaction rate
The slope of the line joining two points along the curve over a given period of time
Average reaction rate
The rate of a reaction at a specific instant
Instantaneous reaction rate
The instantaneous rate at the moment reactants are mixed
Initial reaction rate (t=0)
What is the general rate law?
Rate=k[A]^m[B]^n
A mathematical equation that describes how the rate of a reaction depends upon the concentrations of each reactant
Rate Law
The power to which the concentration of a reactant is raised in a rate law expression for a reaction
Reaction Order
The proportionality constant that relates the rate of a reaction to the concentration of reactants, at a given temperature
Rate Constant
What is the rate equation for the general reaction aA–>Product that is a first order reaction?
Rate = -Δ[A]/Δt = k[A]^n
A mathematical expression that describes the change in concentration of a reactant in a chemical reaction with time
Integrated rate law
The time it takes for the reactant concentration to reach half of its initial value
Half-life
What is the half-life equation for a first order reaction?
t1/2=ln2/k or t1/2=0.693/k
What is the half-life equation for a second order reaction?
t1/2=1/kA
What is the half-life equation for a zero order reaction?
t1/2=A/2k
The minimum amount of energy required to initiate a chemical reaction and is specific to a particular reaction
Activation energy, Ea
Shows temperature dependence of the rate constant, k
Arrhenius Equation: k=Ae(-Ea/RT)
What equation would you use to determine activation energy?
ln k = -Ea/RT +ln A
The individual steps that make up a reaction mechanism
Elementary reactions
The number of reactant particles involved in an elementary step
Molecularity
What are the 3 criteria for proposing a mechanism?
- ) The elementary steps must add up to the overall balanced equation
- ) The elementary steps must be reasonable
- ) Rate limiting must have the same rate law as that determined from experimental data
Provides an alternative route for the reaction with a lower activation energy
Catalyst
