Relative Rate

The relative rate of a reaction is calculated using which formula?

• Relative rate = change in quantity ÷ time

• Relative rate = 1 ÷ time

• Relative rate = time ÷ change in quantity

• Relative rate = concentration × time

What is the correct unit for relative rate?

• s

• s⁻¹

• mol

• mol l⁻¹ s⁻¹

A reaction takes 20 seconds to complete. What is the relative rate of reaction?

• 0.05 s

• 20 s⁻¹

• 0.05 s⁻¹

• 2 s⁻¹

Relative rate is used when:

• A rate is being measured exactly

• No change in quantity can be measured

• Only the time taken for a visible change is recorded

• The final mass of product is known

Which of the following would provide valid data for a relative rate calculation?

• The exact concentration of reactants

• The time taken for a visible change

• The final temperature of the reaction

• The initial mass of reactants

A reaction has a relative rate of 0.2 s⁻¹. How long did the reaction take?

• 2 seconds

• 0.2 seconds

• 5 seconds

• 10 seconds

When comparing two reactions, the one with the greater relative rate:

• Produces more product

• Occurs more slowly

• Takes less time to complete

• Has a lower activation energy

A student records the time taken for a colour change in four reactions. Which reaction has the highest relative rate?

• 8 seconds

• 4 seconds

• 12 seconds

• 10 seconds

What does a higher value for relative rate indicate?

• A slower reaction

• A faster reaction

• A more concentrated solution

• A more accurate result

In an experiment, the time taken for a reaction is halved. What happens to the relative rate?

• It doubles

• It halves

• It stays the same

• It decreases slightly