Under certain conditions, the bromination of cyclohexene follows an unusual rate law:

c. What is the overall kinetic order?

Verified step by step guidance

1. Step 1: Analyze the given rate law: rate = k_r[cyclohexene][Br_2]^2. This equation shows how the reaction rate depends on the concentrations of cyclohexene and bromine.
2. Step 2: Identify the exponents in the rate law. The exponent for [cyclohexene] is 1, and the exponent for [Br_2] is 2.
3. Step 3: Recall that the overall kinetic order of a reaction is the sum of the exponents in the rate law. In this case, add the exponents: 1 (for cyclohexene) + 2 (for Br_2).
4. Step 4: Interpret the chemical reaction. Cyclohexene reacts with bromine (Br_2) to form a dibrominated cyclohexane product. The unusual rate law indicates a second-order dependence on bromine concentration.
5. Step 5: Conclude that the overall kinetic order is determined by summing the individual orders of reactants in the rate law.

Key Concepts

Rate Law

The rate law of a chemical reaction expresses the relationship between the rate of the reaction and the concentration of its reactants. It is typically formulated as rate = k[A]^m[B]^n, where k is the rate constant, and m and n are the orders of the reaction with respect to reactants A and B. Understanding the rate law is crucial for determining how changes in concentration affect the reaction rate.

Kinetic Order

The kinetic order of a reaction is the sum of the exponents in the rate law equation. It indicates how the rate of reaction is affected by the concentration of the reactants. In the given rate law, rate = Kr[cyclohexene][Br2]^2, the order with respect to cyclohexene is 1 and with respect to Br2 is 2, leading to an overall kinetic order of 3.

Bromination of Cyclohexene

Bromination of cyclohexene is an electrophilic addition reaction where bromine (Br2) adds across the double bond of cyclohexene. This reaction can exhibit unusual kinetics under certain conditions, such as the presence of a catalyst or specific solvent effects, which can lead to a rate law that deviates from typical expectations, as seen in the provided rate expression.