Question

2H2(g)+2NO(g)→2H2O(g)+N2(g) Part A If the concentration of NO changed from 0.100 M to 0.025 M in the first 15 minutes of the reaction, what is the average rate of the reaction during this time interval?

Answer 1

Answer:

0.0025 M/min

Explanation:

The rate of a reaction can be calculated for an element, based on its stoichiometric coefficient. For a reaction:

aA + bB = cC + dD , the rate will be

r = -(1/a)x(Δ[A]/Δt) = -(1/b)x(Δ[B]/Δt) = (1/c)x(Δ[C]/Δt) = (1/d)x(Δ[D]/Δt)

Where Δ[X] is the variation of the concentration of the X compound, Δt is the time variation, and the signal of minus in the reagents compounds is because they are disappearing, so Δ[X] will be negative, and r must be positive. So, for the reaction given:

r = -(1/2)x(Δ[NO]/Δt)

r = -(1/2)x( (0.025 - 0.1)/15)

r = 0.0025 M/min