SACE Stage 2 Chemistry 2.1 Rates of Reaction

What can be used to compare the rates of a reaction at different times?

• Slope of a graph of quantity of reactant

• Color change in the reactant

• Temperature of the surroundings

• Time elapsed since the reaction started

Which of the following is NOT a factor that influences the rate of reaction according to the text?

• Presence of a catalyst

• State of matter

• Surface area

• Concentration

What does an energy profile diagram NOT typically show?

• Activation energy

• Relative enthalpies of reactants and products

• Reaction duration

• Enthalpy change for a chemical reaction

Which of the following can change with time and be used to measure the rate of a chemical reaction?

• Mass

• Color of reactants

• Temperature of reactants

• Odor of reactants

How can the rate of a chemical reaction be measured?

• By the change in volume of reactants

• By the change in color intensity

• By the pH change of the solution

• By the electrical conductivity change

What is measured using a gas syringe in the example provided?

• Volume of Hydrogen gas

• Mass of Zinc metal

• Concentration of Hydrochloric acid

• Temperature of the reaction mixture

What does a steep gradient on a quantity-time graph indicate about the rate of a chemical reaction?

• The reaction is at equilibrium

• The reaction is occurring rapidly

• The reaction has stopped

• The reaction is occurring slowly

Which type of reaction involves a net release of energy?

• Endothermic reaction

• Both exothermic and endothermic reactions

• Neither exothermic nor endothermic reactions

• Exothermic reaction

What is represented by the horizontal axis in an energy profile diagram of a chemical reaction?

• The change in reaction rate

• The progression of the reaction from reactants to products

• The change in energy or enthalpy of the system

• The time elapsed during the reaction

What is the sign of the change in energy (ΔE) for an exothermic reaction?

• Positive

• Negative

• Zero

• Infinite