Support learners to think about concentration of acids in moles and link their understanding at three different conceptual levels
Sulfuric acid is a solution of H2SO4 in water. A concentration of 1 mol/dm3 means that 1 mole of H2SO4 is dissolved in 1 dm3 of water. The concentration can be used to determine the number of H+ and SO42- ions that are dissolved.
-
Download this
Use this student worksheet to think about concentration of acids in moles and link to learners' understanding at three different conceptual levels.
View and download more Johnstone's triangle worksheets
Learning objectives
- Describe how to test if a solution is acidic.
- Use appropriate units to write the concentration of an acid from a description.
- Calculate the number of ions in a given concentration of an acid.
How to use Johnstone’s triangle
Use Johnstone’s triangle to develop learners’ thinking about scientific concepts at three different conceptual levels:
- Macroscopic: what we can see. Think about the properties that we can observe, measure and record.
- Sub-microscopic: smaller than we can see. Think about the particle or atomic level.
- Symbolic: representations. Think about how we represent chemical ideas including symbols and diagrams.
For learners to gain a deeper awareness of a topic, they need to understand it at all three levels.
When introducing a topic, do not try to introduce all of the levels of thinking at once. This will overload working memory. Instead complete the triangle over a series of lessons, beginning with the macroscopic level and introducing other levels, in turn, once secure.
All of the levels are interrelated, for example, learners need visual representation of the sub-microscopic in order to develop mental models of the particle or atomic level.
Further reading
Read more about how to use Johnstone’s triangle in your teaching with these articles:
- Develop deeper understanding with models
- Improve students’ understanding with Johnstone’s triangle
- Practical ideas for using Johnstone’s triangle
Norman Reid’s book The Johnstone triangle: the key to understanding chemistry provides a more in-depth overview, the first chapter is available to read online.
Scaffolding
Share the structure of the triangle with learners prior to use. Tell them why you are using it and how it will help them to develop their understanding. Use an ‘I try, we try, you try’ approach when introducing Johnstone’s triangle for the first time.
More resources
To further develop learner’s thinking in all areas of Johnstone’s triangle, try our Developing understanding of concentration and moles worksheet. This inlcudes icons in the margin referring to the conceptual level of thinking needed to answer the questions.
Downloads
Concentration of acids Johnstone's triangle student sheet
Handout | PDF, Size 0.23 mbConcentration of acids Johnstone's triangle teacher notes
Handout | PDF, Size 0.25 mbConcentration of acids Johnstone's triangle student sheet
Editable handout | Word, Size 0.55 mbConcentration of acids Johnstone's triangle teacher notes
Editable handout | Word, Size 0.55 mb
- Prepare(5)
Ideas5 ways to teach excess and limiting reagents to 14–16 learners
Tips for helping learners get to grips with this tricky part of quantitative chemistry
NewsWhat is difficult about concentration?
Fresh insight offers tips for teaching the mathematics of moles, volume and molarity
Ideas5 ways to explain titration
From modelling to scaffolding, these tips will help students master this tricky topic
CourseQuantitative chemistry | Self-led course
Build confidence in your quantitative chemistry knowledge and discover effective topic-specific teaching strategies
CPD articleMoles and titrations
Dorothy Warren describes some of the difficulties with teaching this topic and shows how you can help your students to master aspects of quantitative chemistry
- Deliver(10)
ResourceConcentration of solutions and titration | Structure strip | 14–16 years
Support learners to write about concentration of solutions and titration, using scaffolded writing prompts
Lesson planMeasuring vitamin C in fruit using a microscale titration | 14–16 years
Compare the amount of vitamin C in fruit and juices using a microscale titration in this practical lesson plan with follow-up questions
currently reading
ResourceConcentration of acids | Johnstone’s triangle worksheets | 14–16 years
Learners connect their understanding of dissolved ions, concentration and how chemicals are labelled with this single-page worksheet
ResourceDetermining unknown concentration | Johnstone’s triangle worksheets | 14–16 years
Guide learners to connect their thinking about calculating unknown concentrations following a titration
ResourceConcentration and moles | Developing understanding | 14–16 years
Support learners to develop secure mental models of how concentration is measured and calculated in mol/dm3
ResourceConcentration and mass | Developing understanding | 14–16 years
Encourage learners to deepen their understanding of concentration and mass from the macroscopic to sub-microscopic level
ResourceConcentration of sodium hydroxide | Johnstone’s triangle worksheets | 14–16 years
Think about sodium hydroxide (NaOH) solution at a macroscopic, sub-microscopic and symbolic level
Class experimentA microscale acid–base titration
Use microscale titration to complete an acid–base neutralisation with sodium hydroxide in this class practical. Includes kit list and safety instructions.
Practical videoSimple titration – practical videos | 14–16 students
Video resources showing how to carry out a titration experiment and interactive resources to allow students to collect their own results.
Class experimentUsing indigestion tablets to neutralise an acid | 14-18 years
Investigate and measure the neutralising effect of indigestion tablets (antacids) on hydrochloric acid in this class practical. Includes kit list and safety instructions.
- Literacy(1)
ResourceQuantitative chemistry | Key terms support | 14–16
Language support pack for quantitative chemistry, with key terms list, accessible glossary, Frayer models and unscrambling definitions
- Assess(4)
ResourceConcentration of solutions and titration | In context | 14–16
Put concentration of solutions and titration into context with questions based on acids in fruit juices
ResourceConcentration of solutions and titration | Knowledge check | 14–16
Assess learning of concentration of solutions and titration with a higher and foundation worksheet
ResourceQuantitative chemistry | Review my learning | 14–16 years
A set of differentiated worksheets with answers to identify learning gaps and misconceptions on the topic of quantitative chemistry
QuizAmounts in solution and titrations | Bridging the knowledge gap | 14–16 years
Support your students with the transition to post-16 study with this quiz on amounts in solution and titrations
- Enrich(5)
Lesson planCalculating and comparing solution concentrations | 16–18 years
Use this lesson plan to practise calculating the concentration of a solution from the mass of solute and volume of water
Job profileScientist, food and pharmaceuticals
Taryn uses scientific instruments to test our food and medicines and make sure they are safe
Class experimentAcid–alkali conductometric titration worksheet | 14–16 years
Develop your learners’ understanding of ions and the changes in ionic concentrations in an acid-alkali neutralisation
Job profileBioanalytical scientist
Claire’s work involves stress testing new medicines in various stages of drug development to ensure they are robust and reliable before being released onto the consumer market
ResourceTitration screen experiment
Give students the opportunity to conduct their own titration experiment on a computer or tablet. This resource also includes a redox titration experiment.
No comments yet