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New
Year 10
AQA
Foundation

Water sample analysis: dissolved solids

I can apply techniques to analyse water samples containing dissolved substances.

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Share activities with pupils
New
New
Year 10
AQA
Foundation

Water sample analysis: dissolved solids

I can apply techniques to analyse water samples containing dissolved substances.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. Data can be analysed to assess the purity of water samples containing dissolved solids.
  2. Evaporation set-ups can be used to collect dissolved solids from a water sample.

Common misconception

All water is the same.

The dissolved solid content of water samples is affected by the environment from which it was obtained.

Keywords

  • Sample - A smaller portion of a larger quantity of a substance.

  • Dissolve - When a substance's particles separate and spread throughout the particles of a solvent resulting in it no longer being seen.

  • Analysis - Process of separating and quantifying the components of a sample to understand its nature and composition.

It is useful to trial the practical first so you get a rough idea of the volume of each sample to use, expected results and how long the practical may take to complete. Ensure the water bath in the beaker does not boil dry.
Teacher tip

Equipment

Four glass beakers, four large watch glass, tripod, gauze, Bunsen burner, heatproof mat, samples of 'pure', 'sea', 'rain' and 'ground' water, dropping pipettes, balance measuring to 2 decimal places.

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.
Which of the following describes a solution?
A mixture of two or more insoluble substances.
Correct answer: A mixture where the solute is completely dissolved in the solvent.
A mixture where the solute particles are visible.
Q2.
What is the main purpose of the evaporation process in water sample analysis?
To change the colour of the liquid.
To dissolve more solids into the solvent.
Correct answer: To separate dissolved solids by converting the solvent into a gas.
Q3.
What is the term for a substance that dissolves in a solvent to form a solution?
Mixture
Correct answer: Solute
Solvent
Q4.
Which apparatus is used to accurately measure the volume of a liquid?
Balance
Correct answer: Measuring cylinder
Ruler
Q5.
Why is it important for solute particles to spread evenly throughout the solvent in a solution?
To allow the solute to settle at the bottom.
Correct answer: To ensure the solution is homogeneous and consistent.
To make the solute float on the surface.
Q6.
What happens to the solute particles during the dissolution process?
They react chemically with the solvent.
They remain intact and visible.
Correct answer: They separate and spread throughout the solvent particles.

Exit quiz

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6 Questions

Q1.
What process is used to separate dissolved solids from a liquid?
Decanting
Correct answer: Evaporation
Filtration
Q2.
How can you calculate the concentration of dissolved solids in a water sample?
By adding the mass of dissolved solids to the volume of the water sample.
Correct answer: By dividing the mass of dissolved solids by the volume of the water sample.
By multiplying the mass of dissolved solids by the volume of the water sample.
Q3.
Why is it important to compare data from different water samples?
To change the colour of the water.
Correct answer: To draw conclusions about water quality.
To measure the temperature of the water.
Q4.
What should you do after heating the water sample in the evaporation process?
Add more water to the sample.
Correct answer: Collect and record the mass of the remaining dissolved solids.
Measure the volume of the evaporated solvent.
Q5.
A 30 cm³ water sample contained 0.20 g of dissolved solids. What mass of dissolved solids is in a 5 cm³ sample?
Correct answer: 0.033 g
0.10 g
0.50 g
Q6.
Students heated 10 cm³ of a water sample in a 95.56 g evaporation dish, until dry. Which sample is pure water?
Correct answer: Sample A = 95.56 g
Sample B = 95.58 g
Sample C = 95.93 g