Reaction Rates and Chemical Equilibrium Flashcards

Flashcards based on lecture notes for reviewing reaction rates, chemical equilibrium, and Le Châtelier's principle.

During a chemical reaction, the concentration of __ typically decreases as the reaction progresses.

decrease

During a chemical reaction, the concentration of __ typically increases as the reaction progresses.

increase

ΔH is equal to __.

Hproducts − Hreactants

A reaction with a negative ΔH is considered __.

Exothermic

A reaction with a positive ΔH is considered __.

Endothermic

The three conditions that must be satisfied for a chemical reaction to occur are __, __ and __.

Collision, Orientation, Energy

The __ is the minimum amount of energy required to break the bonds between atoms of the reactants.

Activation Energy

The rate of a chemical reaction can be influenced by changes in __, __ and the presence of a __.

Temperature, Concentration, Catalyst

Increasing the temperature of a reaction mixture generally __ the rate of a chemical reaction.

increases

Increasing the concentration of reactants generally __ the rate of a chemical reaction.

increases

Adding a __ to a reaction mixture increases the rate of a chemical reaction by providing an alternative pathway with a lower activation energy.

catalyst

The reaction H2 and I2 react to form HI is the __ reaction.

forward

The reaction HI molecules can dissociate to from H2 and I2 is the __ reaction.

reverse

__ reactions occur in both the forward and reverse directions at the same time.

Reversible

At __, the rate of the forward reaction equals the rate of the reverse reaction.

equilibrium

At __, the concentrations of reactants and products no longer change with time.

equilibrium

The __ is the ratio of products to reactants at equilibrium.

Kc

Kc values are __ dependent.

temperature

If Kc is smaller than 1, more __ are produced from the reverse reaction at equilibrium.

reactants

If Kc is larger than 1, more __ are produced from the forward reaction at equilibrium.

products

The __ is used to determine if a reaction mixture is at equilibrium by comparing its value to Kc.

Qc

__ states that when a stress is placed on a reaction at equilibrium, the system responds by momentarily changing the rate of the forward or reverse reaction in the direction that relieves that stress until the equilibrium is reestablished.

Le Châtelier’s principle

Adding more reactant to a system at equilibrium will shift the equilibrium in the __ direction.

forward

Adding more product to a system at equilibrium will shift the equilibrium in the __ direction.

reverse

Decreasing the volume of a gas mixture at equilibrium will shift the equilibrium in the direction of the __ number of moles.

smaller

Increasing the volume of a gas mixture at equilibrium will shift the equilibrium in the direction of the __ number of moles.

larger

Adding a catalyst to a system at __ does not shift the equilibrium in either direction.

equilibrium