Consider the general reaction: 2 A + b B → c C and the following average rate data over a specific time period / Delta t: - / frac{ / Delta A}{/Delta t} = 0.0080 mol L-1 s-1 - / frac{ / Delta B}{/Delta t} = 0.0120 mol L-1 s-1 / frac{ / Delta C}{/Delta t} = 0.0160 mol L-1 s-1 Determine what the coefficient c could be in the balanced equation. Select one: 1 5 2 3 4

c = 4

Explanation:

In general, for the reaction

a A + b B ⇒ c C + d D

the rate is given by:

rate = - 1/a ΔA/Δt = - 1/b ΔB/Δt = + 1/c ΔC/Δt = + 1/d ΔD/Δt

this is done so as to express the rate in a standarized way which is the same to all the reactants and products irrespective of their stoichiometric coefficients.

For this question in particular we know the coefficient of A and need to determine the coefficient c.

- 1/2 ΔA/Δt = + 1/c ΔC/Δt

- 1/2 (-0.0080) = + 1/c (0.0160 mol L⁻¹s⁻¹)

0.0040 mol L⁻¹s⁻¹ c = 0.0160 mol L⁻¹s⁻¹

∴ c = 0.0160 / 0.0040 = 4