Lectures 8-11

Question 1

Reaction Rates

Answer 1

How we measure rates

Question 2

Rate Law

Answer 2

How the rate depends on the amount of reactants
Rate = k[A]^m[B]^n

Question 2

Integrated Rate Laws

Answer 2

How to calculate the amount left or the time to reach a given amount

Question 3

Half-Life

Answer 3

How long it takes to react 50% of reactants

Question 4

Arrhenius Equation

Answer 4

ln(k1/k2) = (Ea/R)(1/T2 - 1/T1)
k1 and k2 = Rate
Ea = Activation Energy
R = 8.314
T1 and T2 = Temperature
Determines how the rate constant changes with temperature

Question 5

Catalyst

Answer 5

Substances that change the rate of a reaction without being used up in the reaction; lowers the activation energy by changing the mechanism, but never produces more product

Question 6

Orders

Answer 6

Zero Order: The rate of the reaction does not change when you double the concentration; Rate = k[A]^0 = k; Units of k in Ms^-1 OR molL^-1s^-1; t1/2 = [A]0/2k
First Order: The rate of the reaction doubles when you double the concentration; Rate = k[A]; Units of k in /s or s^-1; t1/2 = ln(2)/k = 0.693/k
Second Order: The rate quadruples when you double the concentration; Rate = k[A]^2 = k[A][B]; Units of k in M^-1s^-1 OR Lmol^-1s^-1; t1/2 = 1/k[A]0

Question 7

Activation Energy

Answer 7

Energy needed to initiate a reaction (overcome reaction barrier)