Given the rate expression, the rate constant can easily be calculated by substituting the rate
and concentrations for any of the four trials into the rate expression; the rate constant will
work out to 3.5 in each case.Trial 1: 0.035 = k[0.10]^2 [1]0.5 : k = 3.5
Trial 2: 0.070 = k[0.10]^2 [4]0.5 : k = 3.5
Trial 3: 0.140 = k[0.20]^2 [1]0.5 : k = 3.5
Trial 4: 0.140 = k[0.10]^2 [16]0.5 : k = 3.5To solve for y, follow the steps as in A. In experiments 1 and 2 (and 2 and 4) [A] is held
constant, the concentration of B quadruples, and the rate doubles. The rate, therefore,
varies as the square root of the concentration of B. The order, y, is therefore equal to 0.5.C. rate = k[A]^2 [B]0.5
D. 2.5
E. 3.54 . rate = k[A] 0 = k
This reaction has only one reactant. It is evident from the data that the rate of the
reaction is not affected by reactant concentration. This is a zero-order reaction, and the
rate is equal to its rate constant, k.
A.
B. k = 0.6
The most likely reason for the increased rate in trial 2 is a change in temperature or the
addition of a catalyst. The rate is still independent of the reactant concentration, but is
faster overall. This increase can only come from an increase in the value of the rate
constant, which is affected by temperature and the activation energy, which in turn is
lowered in the presence of a catalyst.C.
5 . X = 0.3
To calculate X, first write the rate expression for this reaction. From the data, the rate
expression is calculated as:rate = k[SO 3 ]^2 [H 2 O]