Question

A + 2 B + 4 C → products is known to be second order in A, first order in B and independent of the concentration of C. What is the value of the rate constant for this reaction if its rate is 0.783 M · s−1 when [A] = 5.00 M, [B] = 7.00 M, and [C] = 3.00 M? −2 −1 Answerinunitsof M ·s .

Answer 1

Answer:

4.47 × 10⁻³ M⁻² s⁻¹

Explanation:

Let's consider the following generic equation.

A + 2 B + 4 C → products

This reaction is known to be second order in A, first order in B and independent of the concentration of C (zero order in C). The rate law is:

rate = k × [A]² × [B] × [C]⁰

rate = k × [A]² × [B]

where k is the rate constant

When the rate is 0.783 M/s, [A] = 5.00 M, [B] = 7.00 M, and [C] = 3.00 M, the rate constant is:

k = rate / [A]² × [B]

k = 0.783 M/s / (5.00)² × (7.00) = 4.47 × 10⁻³ M⁻² s⁻¹