Unit 11: Chemical Kinetics

These flashcards cover the key concepts and definitions related to chemical kinetics discussed in the lecture notes.

What is the rate of a chemical reaction?

The change in concentration of reactants or products over elapsed time.

Define the method of initial rates.

A technique used to determine rate laws from experimental data by measuring the rate of reaction at the start.

How can graphical methods help in determining rate laws?

Graphical representation of concentration vs. time can provide a visual method to ascertain the order of the reaction.

What is the rate-determining step?

The slowest step in a multi-step reaction which limits the overall reaction rate.

How is the activation energy calculated?

It can be determined from experimental data using the Arrhenius equation.

What role does a catalyst play in chemical reactions?

A catalyst speeds up a reaction without being consumed, facilitating the reaction pathway.

What is the difference between thermodynamics and kinetics?

Thermodynamics studies the stability and spontaneity, while kinetics focuses on the speed of reactions.

What is the equation used to define reaction rates?

Rate = change in concentration / elapsed time.

What does the notation 2A + B → 2C signify?

This represents the stoichiometric coefficients in a chemical reaction.

What does the rate law for a reaction express?

It expresses the relationship between the rate of a reaction and the concentration of reactants.

What is the significance of average and instantaneous rates?

Average rate is the change over a period, while instantaneous rate is the rate at a specific moment.

How do two reactants affect the reaction rate under first-order conditions?

In a first-order reaction with respect to one reactant, the rate is directly proportional to its concentration.

What types of catalysts are there?

Homogeneous catalysts (same phase as reactants) and heterogeneous catalysts (different phase from reactants).

Describe the zero-order integrated rate law.

For a zeroth-order reaction: [A]t = [A]0 - kt, indicating that concentration decreases linearly with time.

What is molecularity in a reaction mechanism?

Molecularity indicates the number of reactant molecules involved in an elementary reaction.