Chemical Kinetics Tutorials
1. Consider the reaction.
2HBr(g)
H2(g) + Br2(g)
a. Express the rate of the reaction in terms of the change in concentration of each of the reactants
and products.
b. In the first 25.0 s of this reaction, the concentration of HBr drops from 0.600 M to 0.512 M.
Calculate the average rate of the reaction during this time interval.
2. For the reaction 2A(g) + B(g)
3C(g),
a. Determine the expression for the rate of the reaction in terms of the change in concentration of
each of the reactants and products.
3. Consider the tabulated data showing the initial rate of a reaction (A
products) at several
different concentrations of A. What is the order of the reaction? Write a rate law for the reaction
including the value of the rate constant, k.
[A] (M)
Initial Rate (Ms-1)
0.100
0.053
0.200
0.210
0.300
0.473
4. This reaction is first order in N2O5:
N2O5(g) →NO3(g) + NO2(g)
The rate constant for the reaction at a certain temperature is 0.053s-1.
a. Calculate the rate of the reaction when [N2O5] = 0.055 M.
b. What is the rate of the reaction at the concentration indicated in part a, if the reaction is second
order? Zero order? (Assume the same numerical value for the rate constant with the appropriate
units.)
5. A reaction in which A, B, and C react to form products is first
order in A, second order in B, and zero order in C.
a. Write a rate law for the reaction.
b. What is the overall order of the reaction?
c. By what factor does the reaction rate change if [A] is doubled (and the other reactant
concentrations are held constant)?
d. By what factor does the reaction rate change if [B] is doubled (and the other reactant
concentrations are held constant)?
e. By what factor does the reaction rate change if [C] is doubled (and the other reactant
concentrations are held constant)?