Concentration of solutions: using moles
Lesson details
Learning outcome
I can explain what is meant by the concentration of a solution and calculate it for various solutions.
Key learning points
- Concentration of an aqueous solution is the mass of solute dissolved in 1 dm³ of distilled water, in g/dm³.
- The mass of one mole of solute is equal to the relative mass of the solute measured in grams.
- Concentration can be expressed in g/dm³ or mol/dm³.
- Equal volumes of solutions of the same concentration (in mol/dm³) have equal numbers of dissolved solute particles.
- Volume can be measured in various units; 1 dm³ is equivalent to 1000 cm³.
Keywords
Solution - Substance formed when a solute dissolves into a solvent.
Solute - A substance that has dissolved into a solvent.
Concentration - The amount of a solute dissolved in a certain volume of solvent.
Dilute - A low concentration of a solute in a solution.
Mole - 6.02 × 10²³ of something. The mass of a mole of a substance is its relative mass expressed in grams.
Common misconception
Pupils often confuse the chemical definitions for 'concentration' and 'strength'.
Stress that concentration is a measure of particles interspersed throughout a specific volume of liquid.
Teacher tip
Use a circus of stations to to build connections between practical and theoretical work. At each station pupils measure out set masses / volumes to create a solution, then calculate the solution's concentration in mol/dm³. Once complete, pupils could rank each solution from most to least dilute.
Equipment
Each station: common solute, spatula, weigh boat, balance, measuring cylinder, access to distilled water, conical flask / beaker + stirring rod
Content guidance
Risk assessment required - equipment
Supervision
Adult supervision required
Licence
Lesson video
Loading...
Prior knowledge starter quiz
6 Questions
Q1.Match each keyword to the correct definition.
a substance formed when a solute dissolves into a solvent
a substance that has dissolved into a solvent
a substance into which a solute dissolves
Q2.Which solution will have the highest concentration?
Q3.Put these solutions in order from the least to the most concentrated.
Q4.How many dm³ is 6500 cm³?
Q5.Which equation correctly links mass, relative mass and moles?
Q6.What is the concentration of an aqueous solution if 20 g of solute is dissolved in 2 dm³ of water?
Assessment exit quiz
6 Questions
Q1.How many cm³ are there in 3 dm³ of solution?
Q2.Which of the following statements correctly describes the concentration of an aqueous solution?
Q3.What is the mass of one mole of sodium chloride (NaCl)? Sodium has a relative atomic mass of 23; chlorine has a relative atomic mass of 35.5.
Q4.What is the mass of solute in a 1 dm³ solution with a concentration of 15 g/dm³?
Q5.Two 500 cm³ solutions of NaCl and KCl both have a concentration of 1 mol/dm³. Which of the following statements is true?
Q6.If the concentration of a solution is 2 mol/dm³, how many moles of solute are there in 500 cm³ of solution?
To help you plan your 10 chemistry lesson on: Concentration of solutions: using moles, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 chemistry lesson on: Concentration of solutions: using moles, 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 Making salts unit, dive into the full secondary chemistry curriculum, or learn more about lesson planning.