Chemistry Test 2: Kinetics and Equilibrium Practice Flashcards

This set of vocabulary flashcards covers key concepts from the Test 2 spring 2026 chemistry exam transcript, including kinetics, catalysis, and chemical equilibrium.

Homogeneous catalyst

A catalyst that is in the same phase as the reactants and products.

Heterogeneous catalyst

A catalyst that is in a different phase from the reactants and products.

Collision theory

A model that assumes the rate of a reaction depends on both the energy of collisions and the orientation of colliding molecules.

Chemical equilibrium

The state of a chemical reaction where the rates of the forward and reverse reactions are equal.

Reaction Quotient ($Q$)

A value compared to the equilibrium constant $K$; if $K$ is larger than $Q$, the forward reaction is faster and $Q$ will increase until equilibrium is reached.

Intermediate

A species in a reaction mechanism that is produced in one step and subsequently consumed in a later step.

Elementary steps

A series of simple molecular steps that constitute a reaction mechanism.

Molecularity

The number of molecules or atoms involved in an elementary step, such as unimolecular or bimolecular.

RICE table

A systematic method for calculating equilibrium concentrations using the row labels Reaction, Initial, Change, and Equilibrium.

Catalyst (in a mechanism)

A species that is present at the beginning of the reaction, consumed in an early step, and then regenerated in a later step.

Half-life ($t_{1/2}$)

The amount of time required for the concentration of a reactant to decrease to half of its initial value.

Partial orders

The exponents in a rate law that define the relationship between the concentration of specific reactants and the reaction rate, determined by experiment.

Total order

The sum of the partial orders in a chemical rate law.

Transition state

The highest energy point in a reaction profile representing the arrangement of atoms at the point of least energetic collision required for reaction.

Equilibrium Constant ($K_c$ and $K_p$ relation)

These values are identical for a gas-phase equilibrium specifically when there is no change in the total number of moles of gas in the reaction.

First-order rate constant units

The units for the rate constant $k$ in a first-order reaction are typically expressed as $1/s$ or $s^{-1}$.

Catalyst effect on equilibrium

An effect where both the forward and reverse reaction rates increase, but the quantity of products at equilibrium remains unchanged.

Average rate of reaction

The speed of a reaction calculated as the change in concentration over a specific time interval, such as $rac{ ext{change in concentration}}{ ext{change in time}}$.