Express the rate of reaction in terms of the change in concentration of each of the reactants and products: a(g) + 2b(g) → c(g) rate = − δ[a] δt = − 2 1 δ[b] δt = δ[c] δt rate = − δ[a] δt = − δ[b] δt = δ[c] δt rate = − δ[a] δt = − 1 2 δ[b] δt = δ[c] δt when [b] is decreasing at 0.28 mol/l·s, how fast is [a] decreasing?