Exercises

Exercise 1. The rate law for the general reaction

aA + bB → cC + dD is Rate = k[A]^m[B]ⁿ. What are the units for k, if the order with respect to [A] is 2 and the order with respect to [B] is 1? The time is measured in hours.

The rate law is, Rate = k[A]²[B]

Solve the rate law for k. \(\displaystyle k\;=\;\frac{Rate}{[A]^2[B]}\;=\;\frac{M/hr}{M^2\times\;M}\)
 
The units of the rate constant are M^-2hr^-1

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Exercise 2. Consider the following reaction.

CH₃Br (aq) + OH^– (aq) → CH₃OH (aq) + Br^– (aq)

The order with respect to each of the reactants is first order. The units of time are seconds.

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Exercise 3. Consider the following reaction.

5 Br^– (aq) + BrO₃^– (aq) + 6 H⁺ (aq) → 3 Br₂ (aq) + 3 H₂O (l)

The reaction is first order in Br^–, first order in BrO₃^– and second order in H⁺. The time was measured in seconds. Write the rate law with the appropriate units.

Rate = [Br^–][BrO₃^–][H⁺]²

The units of the rate law are M^-3s^-1

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