The following reaction:
A + 2B → C
was studied by measuring the [A] as a function of time. Reactant B was always present in excess and it was assumed that the [B] remained essentially constant during the reaction. Shown below is a table of the [A] as a function of time, in seconds. In this experiment, [B] = 3 M.
t (s) [A] (M)
40 0.220
80 0.162
120 0.119
160 0.088
200 0.065
When the [B] was doubled, the rate of the reaction doubled, making it first order in B. Use these data to solve for kapp and k, then select the proper units for kapp and k. Remember that you are measuring the apparent rate constant (kapp) which is related to the true rate constant (k) by the equation kapp = k [B]. To enter an answer in scientific notation, use the convention 1 x 10-3 = 1E-3.
The apparent rate constant, kapp=
The units for kapp are:
M s-1
s-1
M-2s-1
M-1s-1
The true rate constant k=
The units for k are:
M s-1
s-1
M-2s-1
M-1s-1