1. Rate Laws How rate laws are determined ALWAYS experimentally
ALWAYS using reactant concentrations.
Initial rates are used because they are the easiest to measure!

2. A + B  C + D rate=k[A]m[B]n
Where m is the reaction order with respect to A and n is reaction order with respect to B and the overall order is the sum of the exponents (m+n).

3. What does it mean if a reaction is zero order?
Orders of a Reaction
What does it mean if a reaction is zero order?
The change in concentration of reactant has no effect on the rate.
Reaction doesn’t slow down as concentration of reactant decreases.
Rate= k

4. What does it mean if a reaction is first order?
Rate is directly proportional to the reactant’s concentration
doubling [reactant] will double rxn rate
Very common!
Nuclear decay will usually fit in this category
Rate=k[A]

5. What does it mean if a reaction is second order?
Rate is proportional to the square of [reactant]
Rate is quadrupled when [reactant] is doubled and increased by a factor of 9 when [reactant] is tripled, etc…
Common in gas-phase reactions
Rate= k[A]2
or Rate= k[A][B] (first order in respect to A and first order in respect to B, but has an overall order of two)