Concentration and rate: analysis
Lesson details
Learning outcome
I can represent graphically and explain how the rate of reaction depends on the concentration of one of the reactants.
Key learning points
- The changing rate of a chemical reaction can be represented by a graph of volume of gas produced against time.
- When reacting excess acid, the same volume of gas is produced for equal amounts of magnesium.
- Doubling the concentration doubles the rate of reaction.
- The gradient of a rate of reaction graph can be calculated from a tangent drawn at a point on the curve.
Keywords
Gradient - The gradient on a graph represents the rate at which one quantity changes relative to another.
Rate of reaction - Rate of reaction is the speed with which a chemical reaction takes place.
Excess - A reactant in excess is present in a greater amount than is necessary to completely react with the limiting reactant.
Mean rate of reaction - The mean rate of reaction is the average rate at which reactants are converted into products in a given time.
Tangent - A tangent is a straight line that touches a curve at exactly one point without crossing it.
Common misconception
Thinking that as the concentration of a solution in excess changes, so does the volume of gas produced.
The slide deck uses graphical data to show that the same volume of gas is produced when different concentrations are used, so long as the reacting solution is in excess.
Teacher tip
If students have collected data from an investigation on the effect of concentration on rate of reaction, they could use their own data to plot graphs and calculate the mean and instantaneous rate of reaction.
Equipment
Graph paper, ruler (to draw tangent) and calculator.
Licence
except where otherwise stated. See Oak's terms & conditions (Collection 2).Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.How does increasing the concentration of reactants affect the rate of reaction?
Q2.Which of the following will not increase the rate of reaction?
Q3.In the collision theory, what does "successful collision" mean?
Q4.What is the purpose of drawing a tangent to the curve on a rate of reaction graph?
Q5.What does a flat horizontal line on a graph of volume against time indicate?
Q6.For most reactions, when is the rate of reaction highest?
Assessment exit quiz
6 Questions
Q1.What does the gradient of the line on a graph of volume of gas produced against time represent?
Q2.When plotting a graph of the volume of gas produced against time, how would the graph change if the concentration of the reacting solution is increased?
Q3.What happens to the rate of reaction when the concentration of reactants is doubled?
Q4.How can the gradient of the curved section on a rate of reaction graph be determined at a specific point?
Q5.If you use the same mass of magnesium and react it with different concentrations of excess acid, how will this affect the volume of gas produced?
Q6.If two experiments produce the same volume of gas but one reaction takes less time to complete, what can you say about the concentration of reactants?
To help you plan your 11 combined science lesson on: Concentration and rate: analysis, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 11 combined science lesson on: Concentration and rate: analysis, 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 combined science lessons from the Rate of reaction unit, dive into the full secondary combined science curriculum, or learn more about lesson planning.