Using the information in the table, the value of the rate constant for the reaction 2 A(g) + B(g) → C(g) + D(g) is

Question

A₀(M). B₀(M). Rate (M/s)

.100. 2.50 .460

.200. 2.50 .920

.300 1.25 1.38

Answer 1

To find the rate constant (k), we must first determine the order of the reaction and then write the rate law.

Comparing trial 1 to 2, [A] doubles and [B] remains constant. Rate also doubles so this tells us it is FIRST order with respect to A.

Comparing trial 1 to 3, [B] is halved and [A] is tripled. Rate is tripled. This tells us that it is ZERO order with respect to B (since 1st order in A, tripling [A] would triple rate, so [B] had no effect, hence zero order).

Write the rate equation: rate = k[A]

To find value of k, choose any trial (I'll choose trial 1) and solve...

Find value of k: 0.460 M/s = k[0.100]

k = 0.460 M/s / 0.100 M

k = 4.6s^-1