Question

The reaction NO₂(g) + CO(g) → NO(g) + CO₂(g) has been found to be second order with respect to NO₂ and zero order with respect to CO. At a certain temperature, the rate constant is found experimentally to be 3.0 × 10−5 L mol · s . What is the rate of formation of CO₂ at this temperature when the concentration of NO₂ is 4.3 mol/L, that of CO is 6.9 mol/L, that of NO is 7.7 mol/L, and that of CO₂ is 7.6 mol/L? Answer in units of M · s −1 .

a) First, zero
b) Second, zero
c) Zero, second
d) Second, first

Answer 1

The rate of formation of CO₂ for the given reaction can be found using the rate law. By substituting the given concentrations into the rate law equation, we can calculate the rate of formation of CO₂. In this case, the rate of formation of CO₂ is 8.45 × 10⁻⁴ M·s⁻¹.

Step-by-step explanation:

The given rate law for the reaction is rate = k[NO₂]²[CO]º, where the reaction is second order in NO₂ (m=2) and zero order in CO (n=0). Since [CO]° = 1, the concentration of CO can be omitted from the rate law, making the rate of reaction solely dependent on the concentration of NO₂. Therefore, the rate law simplifies to rate = k[NO₂]².

To find the rate of formation of CO₂, we substitute the given concentrations into the rate law equation: rate = k[NO₂]² = (3.0 × 10⁻⁵ mol·L⁻¹·s⁻¹)(4.3 mol/L)² = 8.45 × 10⁻⁴ mol·L⁻¹·s⁻¹.

Therefore, the rate of formation of CO₂ at this temperature is 8.45 × 10⁻⁴ M·s⁻¹.