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Rates Of Reaction

Overview

Chemical reactions happen at different speeds. Fireworks explode in a fraction of a second, while iron rusts over months. Understanding what controls how fast a reaction proceeds is essential for industry, cooking, and everyday safety.

In this lesson you will explore the four key factors that affect reaction rate - surface area, concentration, temperature and catalysts. You will explain each factor using particle collision theory, describe practical investigations, and learn how catalysts provide an alternative pathway with lower activation energy.

Objectives

  1. Describe experiments to investigate the effects of changes in surface area, concentration, temperature and catalysts on the rate of a reaction
  2. Describe the effects of changes in surface area, concentration, pressure, temperature and catalysts on the rate of a reaction
  3. Explain the effects of changes in surface area, concentration, pressure and temperature on the rate of a reaction in terms of particle collision theory
  4. Know that a catalyst is a substance that increases the rate of a reaction but is chemically unchanged at the end
  5. Know that a catalyst works by providing an alternative pathway with lower activation energy
  6. Investigate the effect of changing the surface area of marble chips and of changing the concentration of hydrochloric acid on the rate of reaction
  7. Investigate the effect of different solids on the catalytic decomposition of hydrogen peroxide solution

Lesson Note

A car airbag inflates in under 40 milliseconds because the sodium azide inside it decomposes extremely rapidly. Meanwhile, the stalactites in a cave grow from a reaction that takes thousands of years. The rate at which a chemical reaction happens depends on how often reactant particles collide with enough energy to react. Change the conditions and you change the rate.

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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.

  1. Which factor does NOT affect the rate of a chemical reaction? A) Temperature B) Colour of the reactant C) Concentration D) Surface area Answer: B
  2. A catalyst increases the rate of reaction by: A) Increasing the temperature of the reaction B) Providing an alternative pathway with lower activation energy C) Increasing the concentration of the reactants D) Increasing the surface area of the reactants Answer: B
  3. In the disappearing cross experiment, what substance causes the solution to turn cloudy? A) Sodium chloride B) Sulfur C) Hydrogen chloride D) Sodium thiosulfate Answer: B
  4. When marble chips react with acid, the rate of gas production is fastest at the: A) End of the reaction B) Start of the reaction C) Midpoint of the reaction D) Rate stays constant throughout Answer: B
  5. According to collision theory, a successful collision requires particles to have: A) Any amount of energy B) Energy equal to or greater than the activation energy C) Energy less than the activation energy D) The same speed as each other 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.

Full lesson notes with diagrams
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Study offline, anytime, anywhere
Available on Android, Windows, macOS, and Linux

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.

Full lesson notes with diagrams
AI-powered learning assistant
Study offline, anytime, anywhere
Available on Android, Windows, macOS, and Linux

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