Rates Of Reaction
Overview
Some reactions are over in a flash, like the explosion of a firework. Others take millions of years, like the rusting of iron deep underground. What controls how fast a reaction goes, and how can we speed one up or slow one down?
In this lesson you will learn the five factors that affect reaction rate, explain each one using collision theory, interpret rate graphs, and understand how catalysts work by providing an alternative pathway with lower activation energy. Rates questions appear on both Edexcel papers every session.
Objectives
- describe experiments to investigate the effects of changes in surface area of a solid, concentration of a solution, temperature and the use of a catalyst on the rate of a reaction
- describe the effects of changes in surface area of a solid, concentration of a solution, pressure of a gas, temperature and the use of a catalyst on the rate of a reaction
- explain the effects of changes in surface area of a solid, concentration of a solution, pressure of a gas and temperature on the rate of a reaction in terms of particle collision theory
- know that a catalyst is a substance that increases the rate of a reaction, but is chemically unchanged at the end of the reaction
- know that a catalyst works by providing an alternative pathway with lower activation energy
- draw and explain reaction profile diagrams showing ΔH and activation energy
- practical: investigate the effect of changing the surface area of marble chips and of changing the concentration of hydrochloric acid on the rate of reaction between marble chips and dilute hydrochloric acid
- practical: investigate the effect of different solids on the catalytic decomposition of hydrogen peroxide solution
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Rates Of Reaction. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which factor does NOT affect the rate of reaction? A) Temperature B) Concentration C) Colour of the reactants D) Surface area Answer: C
- A catalyst works by: A) Increasing the temperature B) Providing an alternative pathway with lower activation energy C) Increasing the concentration of reactants D) Being used up in the reaction Answer: B
- On a rate graph, the reaction has finished when: A) The gradient is steepest B) The curve levels off C) The curve starts D) The curve crosses the y-axis Answer: B
- Increasing temperature increases rate because: A) It decreases the activation energy B) It increases the frequency of successful collisions C) It removes the need for collisions D) It creates new reactant particles Answer: B
- Crushing a solid reactant into a powder increases the rate by: A) Lowering the activation energy B) Increasing the surface area exposed to other reactants C) Increasing the mass of the solid D) Changing the products of the reaction Answer: B
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Recommended Books
Practice Mock Questions
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