Rate of a Chemical Reaction – Lesson Summary

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Learning Objective

In this lesson we will learn how the progress of a chemical reaction can be explained by particle collision theory. We will also learn how to measure the rate of a chemical reaction.

Learning Outcomes

By the end of this lesson you will be able to:

  • Define rate of reaction.
  • Describe how the rate of a chemical reaction changes as it progresses.
  • Explain how the progress of a chemical reaction is related to the frequency of successful particle collisions.
  • Measure the instantaneous rate and average rate of a chemical reaction.

 
rate of a chemical reaction

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Lesson Topics

1 | Chemical Kinetics and Collision Theory

2 | The Progress of a Chemical Reaction

3 | Measuring Instantaneous Rate and Average Rate

4 | Summary

Lesson Summary

  • Collision theory states that for a chemical reaction to occur:
  • Reactant particles must collide.
  • Reactant particles must collide with sufficient energy and correct orientation to break bonds.
  • The rate of a chemical reaction refers to how quickly reactants are converted to products.
  • The rate of a reaction can be measured two ways:
  • Instantaneous rate – the rate of change at a particular point in time.
  • Average rate – the rate of change over a particular period of time.
  • Chemical reactions do not proceed at a constant rate.
  • Initially, the reaction is at its fastest, as there is the highest concentration of reactant particles, resulting in the highest frequency of collisions between them.
  • Rate of reaction = maximum.
  • Slope of graph = maximum.
  • Concentration of reactants = maximum.
  • Concentration of products = 0.
  • As a reaction progresses, the rate decreases, as there is a decrease in the concentration of reactant particles, resulting in a decrease in the frequency of collisions between them.
  • Rate of reaction decreases.
  • Slope of graph decreases.
  • Concentration of reactants decreases.
  • Concentration of products increases.
  • Eventually, the reaction stops, as all of the reactants have been converted to products, hence there are no more collisions between reactant particles.
  • Rate of reaction = 0.
  • Slope of graph = 0.
  • Concentration of reactants = 0.
  • Concentration of products = maximum.

 
chemical reaction rate test tube

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