Question 1
Paper 2Medium6 marksNitric oxide is oxidized by oxygen to form nitrogen dioxide:
2NO(g) + O₂(g) → 2NO₂(g)
Initial rates were measured at 298 K.
| Trial | [NO] / mol dm⁻³ | [O₂] / mol dm⁻³ | Initial rate / mol dm⁻³ s⁻¹ |
|---|---|---|---|
| 1 | 0.0200 | 0.0100 | 2.40 × 10⁻⁴ |
| 2 | 0.0400 | 0.0100 | 9.60 × 10⁻⁴ |
| 3 | 0.0200 | 0.0200 | 4.80 × 10⁻⁴ |
At 308 K, an experiment with [NO] = 0.0200 mol dm⁻³ and [O₂] = 0.0100 mol dm⁻³ gave an initial rate of 3.60 × 10⁻⁴ mol dm⁻³ s⁻¹. Assume the rate equation is unchanged between these temperatures.
(a)[2]
Determine the order of the reaction with respect to NO and O₂.
(b)[1]
Write the rate equation for the reaction.
(c)[2]
Calculate the rate constant, k, at 298 K, including its units.
(d)[1]
State which temperature has the larger value of k, using the measurements to justify your answer.