Exam 2

Question 1

Define Molecularity

Answer 1

number of reactant molecules involved in the collision

Question 2

What is the effect in k as the activation energy for a reaction increases

Answer 2

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)

Question 3

What happens to k if you change temp

Answer 3

Increase temp = increase k
Decrease temp = decrease k

Question 4

what is chemical kinetics

Answer 4

study of rate of change of concentrations

Question 5

what is reaction rate

Answer 5

rates of change in concentration of reactants and products over time

Question 6

what impacts reaction rate

Answer 6

1. temperature
   2.concentration/volume/S.A
2. collisions
3. Catalyst

Question 7

what is the collision theory

Answer 7

reaction rate is directly proportional to number of molecular collisions per second

Question 8

what is the activation energy

Answer 8

minimum amount of energy required to initiate a chemical reaction

Question 9

transition state or activated complex

Answer 9

when molecules collide in an effective collisions more activated complex which are the bonds of reactants breaking and bonds of products forming

Question 10

true or false: overall rate of reaction is always positive and has units of concentration over time

Answer 10

true

Question 11

what are relative reaction rates

Answer 11

consumption of reactants and formation of products based on stoichiometry

Question 12

true or false: reaction rates generally decrease over course of reaction

Answer 12

true

Question 13

what is the average reaction rate

Answer 13

change in concentration of reactant or product over a specific time interval

Question 14

what is rate law

Answer 14

relates rate of reaction to the concentrations of reactants - help to classify reactions and then can compare different reactions

Question 15

what is zero order kinetics

Answer 15

rate of reaction is independent of concentration

Question 16

what are reaction mechanisms

Answer 16

reactions could be one step or many discrete steps called elementary process

Question 17

how do we relate reaction rate and reactant concentration

Answer 17

rate law

Question 18

what information is given when we manipulate the initial rate of a reaction?

Answer 18

we can determine how the rate depends on each reactant concentration

Question 19

define first order reactions

Answer 19

rate depends on the concentration of one of the reactants raised to the first power

Question 20

what is half life

Answer 20

time required for reactant concentration to drop half of its original value

Question 21

true or false: half-life of a first-order reaction is independent of the initial concentration of the reactant

Answer 21

true

Question 22

second order half-life

Answer 22

inversely proportional to the initial reactant concentration

Question 23

what is the Arrhenius equation

Answer 23

equation to express dependence of the rate constant of a reaction on the temperature