AP24 Q2 Class 22 (Integrated Rate Laws; Half-Life)

Front

What is the order of a reaction with respect to a reactant?

Back

The order of a reaction with respect to a reactant is the exponent to which the concentration of that reactant is raised in the rate law expression. It indicates how the rate of reaction is affected by changes in the concentration of that reactant.

Front

How do you determine the overall order of a reaction?

Back

The overall order of a reaction is the sum of the orders with respect to each reactant in the rate law. For example, if the rate law is rate = k[A]^2[B]^1.5, the overall order is 2 + 1.5 = 3.5.

Front

What is a half-life in the context of chemical reactions?

Back

Half-life is the time required for the concentration of a reactant to decrease to half of its initial concentration. It is a key concept in first-order reactions and radioactive decay.

Front

What is the relationship between half-life and reaction order?

Back

For first-order reactions, the half-life is constant and independent of the initial concentration. For second-order reactions, the half-life is inversely proportional to the initial concentration.

Front

What does it mean for a reactant to be in excess?

Back

A reactant is in excess when its initial concentration is much greater than that of the other reactants, allowing its effect on the reaction rate to be minimized.

Front

How can you isolate the effect of one reactant on the reaction rate?

Back

To isolate the effect of one reactant, you can ensure that the concentration of the other reactants is much higher than that of the reactant of interest.

Front

What is the integrated rate law for a first-order reaction?

Back

The integrated rate law for a first-order reaction is ln[A] = -kt + ln[A]₀, where [A] is the concentration at time t, k is the rate constant, and [A]₀ is the initial concentration.

Front

How do you calculate the half-life of a first-order reaction?

Back

The half-life (t₁/₂) of a first-order reaction is calculated using the formula t₁/₂ = 0.693/k, where k is the rate constant.

Front

What is the significance of the rate constant (k) in a reaction?

Back

The rate constant (k) is a proportionality factor that relates the rate of a reaction to the concentrations of the reactants. It is specific to a given reaction at a specific temperature.

Front

What is radioactive decay?

Back

Radioactive decay is a first-order process in which unstable atomic nuclei lose energy by emitting radiation, resulting in the transformation of the original element into a different element or isotope.