Rate law for reaction of NO and H2

Chemistry
Thread starter i_love_science
Start date Mar 3, 2021
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Law Rate Reaction

In summary, the rate law for the reaction between NO and H2 is determined experimentally and is dependent on the concentration of reactants. The rate constant (k) is determined by conducting multiple experiments with varying initial concentrations of NO and H2. Factors such as temperature, concentration of reactants, presence of catalysts, and surface area can affect the rate of the reaction. The rate law may be different for the forward and reverse reactions, and it is determined by the slowest step in the overall reaction mechanism.

Mar 3, 2021

i_love_science

Homework Statement: Determine the rate law for this reaction given the data below.

2 NO + 2 H2 -> N2 + 2H2O

Reaction 1:
Initial [NO] = 0.20
Initial [H2] = 0.15
Initial rate = 2.0 * 10^(-4)

Reaction 2:
Initial [NO] = 0.40
Initial [H2] = 0.15
Initial rate = 8.0 * 10^(-4)

Reaction 3:
Initial [NO] = 0.40
Initial [H2] = 0.30
Initial rate = 1.6 * 10^(-3)

I think the rate law is rate = k[NO][SUP]2[/SUP][H2], since when you double the NO concentration, you quadruple the rate.

The solution is rate = k[NO][H2]. Is this wrong? Thanks.

Relevant Equations: rate law

My solution and question are in the homework statement due to some formatting issues. Thanks.

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Mar 3, 2021

mjc123

Science Advisor

Homework Helper

Unless there's an error in the question, you are right. There could easily be a misprint in the solution.

1. What is the rate law for the reaction of NO and H2?

The rate law for the reaction of NO and H2 is determined by the slowest step in the reaction, also known as the rate-determining step. It is expressed as: rate = k[NO]^m[H2]^n, where k is the rate constant and m and n are the reaction orders for NO and H2, respectively.

2. How is the rate constant (k) determined for the reaction of NO and H2?

The rate constant (k) is determined experimentally by measuring the initial rate of the reaction at different concentrations of NO and H2. The values of m and n in the rate law equation can then be calculated using these experimental data, and the rate constant can be determined by plugging in the values of m and n.

3. What factors can affect the rate law for the reaction of NO and H2?

The rate law for the reaction of NO and H2 can be affected by several factors, including temperature, pressure, concentration of reactants, and presence of catalysts. These factors can alter the rate constant and the reaction orders of NO and H2, thus changing the overall rate law for the reaction.

4. How does the rate law for the reaction of NO and H2 relate to the overall reaction mechanism?

The rate law for the reaction of NO and H2 is determined by the slowest step in the overall reaction mechanism. This step is known as the rate-determining step and it controls the overall rate of the reaction. The other steps in the mechanism may occur at a faster rate, but they do not significantly affect the overall rate law.

5. Can the rate law for the reaction of NO and H2 be predicted based on the stoichiometry of the reaction?

No, the rate law for the reaction of NO and H2 cannot be predicted solely based on the stoichiometry of the reaction. It is determined experimentally and may not always follow the expected stoichiometric ratio. The rate law takes into account the specific reaction mechanism and the factors that affect the rate of the reaction.