Consider the combustion of ethylene, C2H4 (g) + 3O2 (g) →2CO2 (g) + 2H2O (g). If the concentration of C2H4 is decreasing at the rate of 3.8*10-2 M/s, what is the rate of change in the concentration of CO2? Express your answer using two significant figures. Δ[CO2]/Δt Δ [ C O 2 ] / Δ t = nothing M/s

0.076 M/s

Explanation:

The rate of a reaction aA + bB → cC + dD can be calculated by:

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)

The minus signal for the reactants is because they're disappearing, so Δ{A] and Δ[B] will be negative. So, for the same time, r is proportional to the coefficients:

r = (1/2) Δ[CO₂]/Δt

Δ[CO₂]/Δt = 2x3.8x10⁻²

Δ[CO₂]/Δt = 0.076 M/s