CHEM 1160- Reaction Rates and Relative Reaction Rates

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 delta[B]/ delta t

What is the rate at which CIO2-(aq) is appearing in the reaction: 2 ClO₂(aq) + 2 OH⁻(aq) → ClO₂⁻(aq) + ClO₃⁻(aq) + H₂O(l)

- +1/1 delta[CIO3-]/delta t - Both CIO2- and CIO3- have positive rates and a #1 coefficient - therefore, delta[CIO3-] can also represent the rate at which CIO2- is appearing

Which species has the greatest rate of disappearance in the reaction below? CH₄ + 2 O₂ → 2 CO₂ + H₂O

- 2 O2 would disappear first during a reaction - The reactants are CH4, and O2. Because there are 2 times as many O2 molecules reacting than in CH4, O2 has the greater rate of disappearance

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

- 2S and 2H2O have the same rate of appearance - From the coefficients in the equation, we can see that 2 molecules of S are produced for every 2 molecules of H2O. Therefore they have identical rates.

Why is the reaction at 60C greater than at 30C?

- Because there is a greater proportion of reactants with the necessary kinetic energy to react - The molecules are moving faster at higher temperatures, increasing the likelihood that they have enough kinetic energy to react

What factors affect the Rate of Reaction?

- Concentration of the reactants - Presence of catalyst - Temperature of the reaction - Surface area of the solid reactants

What factors decrease the Rate of Reaction?

- Removing a catalyst from the reaction - Decreasing the temperature - Decreasing the surface area of a solid reactant - Decreasing the concentration of the reactants

What happens in a reaction at equilibrium?

- The rate of the forward reaction is equal to the rate of the reverse reaction - When a reaction is at equilibrium there is no further change in the concentrations of the reactants/products, meaning, they are formed at the same rate as they are breaking down