Chemistry Sem 2 Unit 5 Reaction Rates and Equilibrium

Which equation is used to describe reaction rates?

• ∆H−T∆S

• S_products−S_reactants

• ∆(reactant or product)/∆time

• pV=nRT

Which term refers to the difference between the energy of the transition state and the energy of the reactants?

• energy of entropy

• energy of enthalpy

• activation energy

• reaction rate energy

What happens to a catalyst as a result of its involvement in a chemical reaction?

• It is consumed.

• It is not consumed.

• It slows a chemical reaction.

• It changes to something else.

What can be calculated if the concentration of a reaction’s products and reactants are known, as well as the coefficients of each in the balanced equation?

• the rate of the reaction

• the equilibrium constant

• the entropy of the reaction

• Gibbs free energy

A chemical reaction is at equilibrium.

What will be the effect if more of the product is added?

• There will be no effect; the reaction will stay at equilibrium.

• The reaction will shift to the left (toward the reactants).

• The reaction will shift to the right (toward the products).

Consider the reaction 2 NaN₃ → 2 Na + 3 N₂, which is the first reaction that occurs when an air bag expands in a car undergoing a collision. This reaction happens very quickly, as you might suspect.

A graph showing the amount of nitrogen gas (N₂) could be best described as which sentence?

• The graph line’s general trend is increasing from left to right.

• The graph line’s general trend is decreasing from left to right.

• The graph line’s general trend is nearly horizontal.

• The graph line’s general trend is absolutely horizontal.

What does the formula ΔH − TΔS determine?

• entropy

• enthalpy

• Gibbs free energy

• Le Châtelier’s principle

What kind of reaction occurs when the entropy change of an endothermic reaction is negative?

• spontaneous

• nonspontaneous at equilibrium

• reversible

• irreversible

Which term describes the effects of changes in concentration on a chemical system in equilibrium?

• Gibbs free energy

• chemical equilibrium

• reaction rate

• Le Châtelier’s principle

Molecules involved in a chemical reaction must meet to react.

What is this called?

• entropy

• enthalpy

• collision theory

• reaction rate