Understanding Reaction Rates in Chemistry

Which of the following will increase the rate of a chemical reaction?

• Decreasing the temperature

• Increasing the concentration of reactants

• Using a smaller surface area of reactants

• Removing a catalyst

According to collision theory, what must happen for a reaction to occur between two particles?

• They must collide with enough energy and correct orientation

• They must be dissolved in water

• They must be heated to 100°C

• They must be in the same physical state

What is the main role of a catalyst in a chemical reaction?

• It increases the temperature of the reaction

• It lowers the activation energy required

• It increases the mass of the products

• It changes the colour of the reactants

Which unit is commonly used to measure the rate of a reaction in terms of gas produced?

How does increasing the temperature generally affect the rate of a chemical reaction?

• It decreases the rate

• It has no effect

• It increases the rate

• It stops the reaction

Which of the following best describes a catalyst?

• A substance that is used up in a reaction

• A substance that speeds up a reaction and is unchanged at the end

• A product of the reaction

• A reactant that slows down the reaction

If the concentration of hydrochloric acid is doubled in a reaction with magnesium, what is likely to happen to the reaction rate?

• It will halve

• It will stay the same

• It will increase

• It will stop

Which of the following is NOT a factor that affects the rate of a chemical reaction?

• Surface area of reactants

• Colour of the reactants

• Temperature

• Presence of a catalyst

What does the term "activation energy" refer to?

• The energy released by the reaction

• The minimum energy required for a reaction to occur

• The energy stored in the products

• The energy needed to cool the reactants

Which method could be used to measure the rate of a reaction that produces a gas?

• Measuring the change in mass of the reaction vessel

• Measuring the temperature of the room

• Measuring the colour of the solution

• Measuring the pH of the solution