A(g) + 3B(g) → 2C(g) Use the tabulated data to answer the questions about this reaction, which is ca — Kinetics Chemistry Question
Problem Context
A(g) + 3B(g) → 2C(g)
Use the tabulated data to answer the questions about this reaction, which is carried out in a 1.0 L container at 25°C.
For experiment 1, give the initial rate of disappearance of
i. A
Model Answer
rate of formation C = 0.25 mol·L-1·min-1 so
i. rate of disappearance of A = 0.25 × 1/2 = 0.13 mol·L-1·min-1
ii. B
Model Answer
ii. rate of disappearance of B = 0.25 × 3/2 = 0.38 mol·L-1·min-1
Determine the orders of A and B and write the rate law for the reaction.
Model Answer
for experiments 2 and 3: [B] is constant while [A] doubles and the rate of the reaction is unchanged. The reaction order with respect to A is zero.
for experiments 3 and 1: [A] is constant while [B] doubles and the rate of the reaction increases by a factor of 8. The reaction order with respect to B is 3.
Rate = k[B]3
Calculate the value of the rate constant and give its units.
Model Answer
k = 0.25 / (0.10)3 = 250 L2·mol-2·min
For the initial amounts of A and B in experiment 1, state the initial rate of formation of C under the following conditions. Justify your answer in each case.
i. 0.50 mol of neon gas is added to the 1.0 L container.
Model Answer
The rate of formation of C is 0.25 mol·L-1·min-1. Adding an inert gas does not change the rate law.
ii. the volume of the container is increased to 2.0 L.
Model Answer
The rate of formation of C is 0.031 mol·L-1·min-1. Doubling the volume of the container changes the concentration of B. [B] = 0.050 mol·L-1
Rate = k[B]3 = 250 L2·mol-2·min (0.050 mol·L-1)3 = 0.031