New
New
Year 10
OCR
Higher

Concentration of solutions

I can explain what is meant by the concentration of a solution and calculate the concentration of various solutions.

New
New
Year 10
OCR
Higher

Concentration of solutions

I can explain what is meant by the concentration of a solution and calculate the concentration of various solutions.

Lesson details

Key learning points

  1. Concentration of a solution is the mass of solute dissolved in 1 dm³ of distilled water, in g/dm³.
  2. The more solute that is dissolved, the more concentrated the solution.
  3. Solutions can be diluted (i.e. made less concentrated) by increasing the volume of distilled water.
  4. Diluting solutions with distilled water ensures no other substances are present in the solution.
  5. Volume can be measured in various units; 1 dm³ is equivalent to 1000 cm³.

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.

Keywords

  • Solution - substance formed when a solute dissolves into a solvent

  • Solute - a substance that has dissolved into a solvent

  • Solvent - a substance into which a solute dissolves

  • Concentration - the amount of a solute dissolved in a certain volume of solvent

  • Dilute - a low concentration of a solute in a solution

Use a circus of stations 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. Once complete, pupils could rank each solution from most to least dilute.
Teacher tip

Equipment

Each station: common solute, spatula, weighing boat, balance, measuring cylinder, access to distilled water, conical flask/beaker + stirring rod.

Content guidance

  • Risk assessment required - equipment
  • Depiction or discussion of violence or suffering

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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6 Questions

Q1.
Match the units to the correct measurement.
Correct Answer:mass,kg

kg

Correct Answer:volume,cm³

cm³

Correct Answer:temperature,

Correct Answer:weight,N

N

Correct Answer:concentration,g/dm³

g/dm³

Q2.
What is the state symbol for water at room temperature?
s
Correct answer: l
g
aq
Q3.
Match the definition with the correct keyword.
Correct Answer:solution,substance formed when a solute dissolves into a solvent

substance formed when a solute dissolves into a solvent

Correct Answer:solute,a substance that has dissolved into a solvent

a substance that has dissolved into a solvent

Correct Answer:solvent,a substance into which a solute dissolves

a substance into which a solute dissolves

Q4.
Which solution will have the highest concentration?
Correct answer: Solution 1 contains 10 g of solute dissolved in 100 cm³ of water.
Solution 2 contains 8 g of solute dissolved in 100 cm³ of water.
Solution 3 contains 5 g of solute dissolved in 100 cm³ of water.
Solution 4 contains 2 g of solute dissolved in 100 cm³ of water.
Solution 5 contains 0.5 g of solute dissolved in 100 cm³ of water.
Q5.
Order these solutions from the least to the most concentrated.
1 - Solution A has a concentration of 0.01 g/dm³
2 - Solution C has a concentration of 0.1 g/dm³
3 - Solution D has a concentration of 1 g/dm³
4 - Solution B has a concentration of 100 g/dm³
Q6.
How many dm³ is 5000 cm³?
0.005
0.5
Correct answer: 5
5000

6 Questions

Q1.
What does the concentration of a solution refer to?
the mass of solvent used
the volume of solvent used
the mass of solute used
the volume of solute used
Correct answer: the mass of solute dissolved in a specific volume of solvent
Q2.
What unit is commonly used to measure the concentration of a solution?
g/mL
Correct answer: g/dm³
N/m³
L/mg
Q3.
How can you increase the concentration of a solution?
by adding more solvent
by diluting the solution
Correct answer: by adding more solute
by decreasing the temperature
Q4.
Convert 2.5 dm³ into cm³?
0.0025
0.25
25
Correct answer: 2500
Q5.
If 10 grams of salt is dissolved in 500 cm³ of distilled water, what is the concentration in g/dm³?
5 g/dm³
10 g/dm³
Correct answer: 20 g/dm³
30 g/dm³
Q6.
How much distilled water needs to be added to 1 dm³ of a 40 g/dm³ solution to dilute it to 20 g/dm³?
0.5 dm³
Correct answer: 1 dm³
2 dm³
4 dm³