2.1 Rates of Reactions (Part 1 of 2)

What can be compared by considering the slope of a graph of quantity or concentration of reactant or product against time?

• Temperature changes in a reaction

• Rates of a reaction at different times

• Pressure changes in the system

• Volume of reactants used

What does the rate of a reaction measure?

• Change in pressure of the system

• Change in volume of the reaction mixture

• Change in the quantity of a substance over time

• Change in temperature over time

What is required to calculate the reaction rate from a graph?

• The initial concentration of reactants

• The highest point on the graph

• The final concentration of products

• Drawing a tangent to the curve

How can the average rate of a reaction be determined from a graph?

• By finding the area under the curve

• By calculating the slope between two points on the graph

• By measuring the height of the graph

• By counting the number of reactant particles

What is another method to observe the reaction rate besides graphing changes over time?

• By observing a change in pH or color intensity

• By adding a catalyst

• By altering the pressure

• By changing the temperature

What do energy profile diagrams represent?

• The volume change in a reaction

• The speed of a reaction

• The temperature change during a reaction

• The relative enthalpies of reactants and products

What is enthalpy?

• The mass content of a system

• The volume content of a system

• The pressure content of a system

• The heat or energy content of a system

What does a negative ΔH value indicate?

• An endothermic reaction

• A reaction that absorbs energy

• A reaction that requires no energy

• An exothermic reaction

What is the activation energy?

• The energy released when new bonds form

• The minimum energy required for reactants to collide and form products

• The total energy of the reactants

• The energy needed to break the container

How can the enthalpy change (ΔH) for a reaction be determined?

• By multiplying the energy of the reactants and products

• By dividing the energy of the reactants by the products

• By adding the energy of the reactants and products

• By subtracting the energy of the reactants from the products