Reaction mechanism and rate law | Kinetics | AP Chemistry | Khan Academy

What is a mechanism in the context of chemical reactions?

A mechanism is the sequence of elementary steps by which a reaction proceeds.

What are the two reactants in the example reaction discussed?

Nitrogen dioxide (NO2) and carbon monoxide (CO).

What does the first step of the proposed mechanism produce?

The first step produces nitric oxide (NO) and nitrate (NO3).

What is the role of an intermediate in a reaction mechanism?

An intermediate is a species that is made in one step and consumed in another step of the mechanism.

What is the rate determining step of the mechanism provided?

The slow step, which is step one, is the rate determining step.

What is the experimental rate law for the overall reaction?

The rate is equal to the rate constant k times the concentration of nitrogen dioxide squared.

Why is the reaction order in carbon monoxide zero?

Carbon monoxide does not appear in the rate law as it is part of the fast step, not the rate determining step.

How do you find the rate law for an elementary reaction?

You take the coefficients of reactants as exponents in the rate law.

What does a second order reaction mean in terms of reactants?

The reaction rate depends on the concentration of one reactant raised to the second power.

How is the total time for the reaction determined in the example?

The total time is the sum of the time taken by the slow step and the fast step.