Chemical Kinetics and Reaction Rates

These flashcards cover key concepts related to chemical kinetics, including rate laws, integrated rate laws for different orders, the effects of temperature on reaction rates, and concepts related to activation energy.

What does the rate law show in relation to chemical reactions?

The rate law shows the relationship between the rate of a reaction and the concentration of reactants.

What is the first-order integrated rate law formula?

ln[A]t = -kt + ln[A]0

In a first-order reaction, what is the relationship between the natural logarithm of the concentration and time?

A plot of ln[A] versus time yields a straight line with a slope of -k.

How do you determine the rate constant from a first-order reaction graph?

The slope of the line in the ln[A] versus time plot equals -k.

What unit is the rate constant k in a first-order reaction?

The unit for the rate constant k in a first-order reaction is s⁻¹.

For a first-order reaction, how is the half-life calculated?

The half-life t1/2 = 0.693 / k.

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

1/[A]t = kt + 1/[A]0.

What characterizes a zero-order reaction in terms of rate law?

The rate is constant and is independent of the concentration of the reactant.

What is the equation for the half-life of a zero-order reaction?

t1/2 = [A]0 / 2k.

How does temperature affect the rate constant k?

The rate constant k is temperature dependent, as described by the Arrhenius equation.

What does the Arrhenius equation express?

The Arrhenius equation expresses the relationship between the rate constant k, temperature T, activation energy Ea, and frequency factor A.

How does increasing temperature affect reaction rates?

Increasing temperature raises the fraction of molecules with sufficient energy to overcome the activation barrier, increasing reaction rates.

What is the activation energy in a chemical reaction?

The activation energy is the minimum energy required for a reaction to occur.

What does the frequency factor in the Arrhenius equation represent?

The frequency factor represents the number of times reactant molecules collide with the correct orientation to form activated complexes.

What is the significance of the exponential factor in the Arrhenius equation?

The exponential factor represents the fraction of molecules that have sufficient energy to overcome the activation energy barrier.

What happens to the thermal energy distribution as temperature increases?

As temperature increases, the fraction of molecules able to surmount the activation energy barrier increases.