Exam 2 Flashcards
(23 cards)
Define Molecularity
number of reactant molecules involved in the collision
What is the effect in k as the activation energy for a reaction increases
From the Arrhenius equation it would result in a decrease for the rate constant (k)
* takes longer to reach top of mountain when the peak is taller ( more activation energy)
What happens to k if you change temp
Increase temp = increase k
Decrease temp = decrease k
what is chemical kinetics
study of rate of change of concentrations
what is reaction rate
rates of change in concentration of reactants and products over time
what impacts reaction rate
- temperature
2.concentration/volume/S.A - collisions
- Catalyst
what is the collision theory
reaction rate is directly proportional to number of molecular collisions per second
what is the activation energy
minimum amount of energy required to initiate a chemical reaction
transition state or activated complex
when molecules collide in an effective collisions more activated complex which are the bonds of reactants breaking and bonds of products forming
true or false: overall rate of reaction is always positive and has units of concentration over time
true
what are relative reaction rates
consumption of reactants and formation of products based on stoichiometry
true or false: reaction rates generally decrease over course of reaction
true
what is the average reaction rate
change in concentration of reactant or product over a specific time interval
what is rate law
relates rate of reaction to the concentrations of reactants - help to classify reactions and then can compare different reactions
what is zero order kinetics
rate of reaction is independent of concentration
what are reaction mechanisms
reactions could be one step or many discrete steps called elementary process
how do we relate reaction rate and reactant concentration
rate law
what information is given when we manipulate the initial rate of a reaction?
we can determine how the rate depends on each reactant concentration
define first order reactions
rate depends on the concentration of one of the reactants raised to the first power
what is half life
time required for reactant concentration to drop half of its original value
true or false: half-life of a first-order reaction is independent of the initial concentration of the reactant
true
second order half-life
inversely proportional to the initial reactant concentration
what is the Arrhenius equation
equation to express dependence of the rate constant of a reaction on the temperature
