Collision theory
Lesson details
Learning outcome
I can explain why increasing pressure, surface area or concentration increases the frequency of collisions between particles and therefore the rate of reaction.
Key learning points
- Particles of reactants in a chemical reaction can react together if they collide with sufficient energy.
- Increasing surface area of a solid lets more reacting particles in a solution collide with its particles each second.
- Increasing concentration of a reacting solution introduces more reactant particles, so they collide more frequently.
- Increasing temperature of reactants increases the speed of particles, so they collide more frequently.
- Increasing pressure of reacting gases pushes reactant particles closer together, so they collide more frequently.
Keywords
Collision theory - The collision theory is that particles must collide, and with sufficient energy, in order to react.
Activation energy - The minimum energy that the particles must have in order to react is known as the activation energy.
Rate of reaction - Rate of reaction is the speed with which a chemical reaction takes place, measured by the amount of a reactant used or amount of product formed in a given time.
Common misconception
That every collision between reactant particles results in a chemical reaction.
The slide deck addresses that not every collision between reactant particles results in a chemical reaction. The particles must collide with the activation energy in order for the collision to be successful and a new product be formed.
Teacher tip
An engaging way to model the idea of increasing concentration, pressure, surface area and temperature is using students to represent the particles in the reactants.
Equipment
None required.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.In the following reaction identify the reactant: hydrogen peroxide → water + oxygen
Q2.Which solution has the highest concentration?
Q3.Which of the following statements about rate of reaction are true?
Q4.A student has 5 g of calcium carbonate. How can they increase the surface area of the calcium carbonate?
Q5.On a volume versus time graph, what does a steep gradient represent?
Q6.Match the key term to the correct definition.
particles must collide, and with sufficient energy, in order to react
the minimum energy that the particles must have in order to react
the amount of chemical dissolved in a certain volume of solution
is the total area of every outer surface of an object
Assessment exit quiz
6 Questions
Q1.Which conditions must particles of reactants meet in order to react in a chemical rection?
Q2.How does increasing the surface area of a solid affect the rate of reaction?
Q3.Why does increasing the concentration of reactants typically increase the rate of reaction?
Q4.What happens when the concentration of a reacting solution is increased?
Q5.What effect does decreasing the pressure of reacting gases have on the rate of reaction?
Q6.What effect does increasing the temperature of reactants have on the rate of reaction?
To help you plan your 10 chemistry lesson on: Collision theory, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 chemistry lesson on: Collision theory, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 chemistry lessons from the Rate of reaction unit, dive into the full secondary chemistry curriculum, or learn more about lesson planning.