Answer:
a) The reaction order in NO is 2
b) The reaction order in O₂ is 2
c) The overall order of the reaction is 4
d) If NO's concentration is halved, the reaction rate is quartered and is equal to 1.5 × 10⁴ M/s.
e) Reaction rate constant, k = 15.197 s/M³ = 15 s/M³ to 2s.f
Explanation:
The reaction order of a reaction with respect to a reactant is the power the reactant carries in the rate law.
a) The reaction order in NO is 2.
b) The reaction order in O₂ is 2.
c) Overall order is the sum of all the powers in the rate law, and for this reaction, it is 2 + 2 = 4
d) If the other parameters are constant, the rate of the reaction is directly proportional to the square of the concentration of NO
r = K [NO]²
At point 1, let r = r₁ and [NO] = [(NO)₁]
At point 2, let r = r₂ and [NO] = [(NO)₂]
r₁ = K [(NO)₁]²
At point 2,
r₂ = K [(NO)₂]²
But [(NO)₂] = [(NO)₁/2]
So, r₂ = K [(NO)₁/2]² = K [(NO)₁]²/4
And r₁ = K [(NO)₁]²,
So, r₂ = r₁/4
Meaning the reaction rate becomes (6.0 × 10⁴)/4 = 1.5 × 10⁴ M/s
e) The rate of the reaction is measured to be 79.0 M / s when [NO] = 1.2 M and [O2] = 1.9 M. Calculate the value of the rate constant.
r = k [NO]² [O₂]²
79 = k × 1.2² × 1.9²
k = 15.197 s/M³