Chapter 12

What is the rate of production of C in the following reaction: A + B → 2 C.

+0.5∆[C]/∆t The rate of a reaction is equal to the rate of change of a reactant or product, divided by its coefficient in the balanced equation. Since reactants are disappearing they have negative values and products have positive values. For the reaction A+B⟶2C the rate in terms of the change in C is given by rate= + 1/2(Δ[C]/Δt) = +0.5Δ[C]/Δt

For the reaction 2 A + 3 B → 4 D + 5 E, how is the rate of reaction expressed in terms of rate of disappearance of B?

-1/3∆[B]/∆t The rate of a reaction is equal to the rate of change of a reactant or product, divided by its coefficient in the balanced equation, with negative values for reactants because they are disappearing and positive values for products. For the given reaction 2A+3B⟶4D+5E the rate in terms of the change is given by rate=−13Δ[B]Δt

For the reaction 3A+4B ---> 2C + 4D, what is the magnitude of the rate of change for [D] when [C] is increasing at 2.0 M/s

4.0 M/s The rate of a reaction is equal to the rate of change of a reactant or product, divided by its coefficient in the balanced equation. Since reactants are disappearing they have negative values and products have positive values. For the reaction 3A+4B⟶2C+4D the rate in terms of the change in B and C is given by Rate=−1/4 (Δ[B]/Δt) = + 1/2 (Δ[C]/Δt) Substituting 2.0 M/s for Δ[C]/Δt and solving for the absolute magnitude of Δ[B]/Δt 1/4 (Δ[B]/Δt) = 1/2 (2.0M/s)= 1.0(M/s) Δ[B]/Δt =4×1.0 M/s = 4.0 M/s

What is the absolute magnitude of the rate of change for [NH₃] if the rate of change for [H₂] is 6.10 M/s in the reaction 2 NH₃(g) → N₂(g) + 3 H₂(g)?

4.07 M/s 2NH₃(g)⟶N₂(g)+3H₂(g) the rate in terms of the change in [NH3] and [H2] is given by Rate=−1/2(Δ[NH3]/Δt)= + 1/3(Δ[H2]/Δt Substituting 2.00 M/s for Δ[H2]/Δt and solving for the absolute magnitude ofΔ[NH3]/Δt 1/2 (Δ[NH3]/Δt) = 1/3 (2.00M/s) = 0.6667 M/s Δ[NH3]/Δt = 2×0.6667M/s = 1.33M/s

For the reaction 2 A + 4 B → 2 C + 4 D, what is the absolute magnitude of the rate of change for [B] when [C] is increasing at 4.8 M/s?

9.6 M/s The rate of a reaction is equal to the rate of change of a reactant or product, divided by its coefficient in the balanced equation. Since reactants are disappearing they have negative values and products have positive values. For the reaction, 2A + 4B⟶ 2C + 4D the rate in terms of the change in B and C is given by Rate = − 1/4(Δ[B]/Δt) Substituting 2.0 M/s for Δ[C]/Δt and solving for the absolute magnitude ofΔ[B]/Δt 1/4 Δ[B]/Δt = 1/2(2.0Ms) = 1.0 (M/s) Δ[B]/Δt = 4×1.0Ms=4.0M/s

Which species has the greatest rate of appearance in the reaction below? 2 H₂S + O₂ → 2 S + 2 H₂O

S and H₂O have identical rates Products appear during a reaction. For the equation given 2H2S+O2⟶2S+2H2O2 the products are S and H2O. From the coefficients in the equation you can see that 2 molecules of S are produced for every 2 molecules of H2O. Therefore, S and H2O have identical rates.