WARM UP “Let us move on and step out boldly, though it be into the night, and we can scarcely see the way.” - Charles B. Newcomb 1)What does this mean to you? 2)How does this apply to Chemistry II right now?

Rate Law Chemistry II

Chemical Kinetics Study of the speed of chemical reactions, the reaction rate –Measured as the change in concentration of a reactant or product over time Δ = change t = time

Simple Rate Expressions For the reaction A  B –rate = - Δ[A] or Δ[B] Δt Δt

Reaction Order Exponents show how concentrations of reactants affect the rate, and sum of the exponents is the reaction order –A  B rate = [A] 3

Reaction Order –Exponent determined experimentally How change in [A] affects rate –order = rate 2 / rate 1 [ ] 2 / [ ] 1 –ex: 1) [A] = 2 M, rate = 10 2) [A] = 4 M, rate = 40 order = 4 / 2 = [A] 2

Rate Constant Rate constant accounts for relationship between rate and concentration –Label is k, unit is variable –Calculation: k = rate [reactants] x

Rate Law Allows quick calculation of rate using rate constant and reaction order –A + B  C + D Rate = k[A] x [B] y

WRAP UP 1) Write the simple rate expression for the following reaction in terms of both the disappearance of the reactants and the appearance of the products: 30 CH 3 OH + B 10 H 14  10 B(OCH 3 ) H 2