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Subjects · Leaving Cert Chemistry

Leaving Cert Chemistry: Concentration

How often Concentration comes up on the Chemistry papers, every year it was asked, and questions to try.

HL Asked on 5 of the last 10 Higher Level papers, most recently in 2025.

OL Asked on 10 of the last 10 Ordinary Level papers, most recently in 2026. banker

June 2027 is the first exam on the new Chemistry course. These come from the 2016–2026 papers, so read them as a guide.

Concentration, Higher Level(8 marks)

Quick ones on Concentration.

(a)Concentration of a solution containing 0.2 mol of solute in 500 cm3?
  1. 0.1 mol l⁻¹
  2. 0.4 mol l⁻¹
  3. 2.5 mol l⁻¹
(b)Apparatus used to make up a standard solution to an exact volume?
  1. Beaker
  2. Conical flask
  3. Volumetric flask
(c)Moles of solute in 250 cm3 of a 0.1 mol l⁻¹ solution?
  1. 0.025 mol
  2. 0.0025 mol
  3. 0.25 mol
Show the answers

(a) 0.4 mol l⁻¹

(b) Volumetric flask

(c) 0.025 mol

Your turn: Higher Level questions on Concentration.

Higher Level

Asked on 5 of the last 10 Higher Level papers, most recently in 2025.

Every paper, year by year

YearWhere it came up
2026Not asked
2025Q4(h)
2024Q1
2023Q4(g)
2022Not asked
2021Not asked
2019Not asked
2018Not asked
2017Q4(f)
2016Q1

Links open the State Examinations Commission’s paper for that year.

More Concentration questions

Concentration, 3 marks

0.002 g of lead is dissolved in 1 litre of water. Concentration in p.p.m.?

  1. 0.002 p.p.m.
  2. 2000 p.p.m.
  3. 2 p.p.m.
Show the answer

2 p.p.m.

0.002 g = 2 mg. In dilute water, 1 mg per litre = 1 p.p.m., so 2 mg per litre = 2 p.p.m.

Ordinary Level

Asked on 10 of the last 10 Ordinary Level papers, most recently in 2026. banker

Every paper, year by year

YearWhere it came up
2026Q2
2025Q2
2024Q2
2023Q2, Q3
2022Q2
2021Q2, Q4(i)
2019Q2, Q3
2018Q2, Q4(i)
2017Q2, Q4(i)
2016Q2

Links open the State Examinations Commission’s paper for that year.

More Concentration questions

Concentration, 3 marks

0.5 mol of sodium chloride is dissolved to make 2 litres of solution. Concentration?

  1. 1.0 mol/L
  2. 2.5 mol/L
  3. 0.25 mol/L
Show the answer

0.25 mol/L

Concentration = moles divided by litres = 0.5 / 2 = 0.25 mol/L.

Concentration, 2 marks

Meaning of 12% (v/v) alcohol on a wine label?

  1. 12 g of ethanol in every litre of wine
  2. 12 cm3 of ethanol in every 100 cm3 of wine
  3. 12 g of ethanol in every 100 g of wine
Show the answer

12 cm3 of ethanol in every 100 cm3 of wine

v/v means volume of solute per 100 volumes of solution. w/v would be grams per 100 cm3.

Concentration, 3 marks

A sodium hydroxide solution is 0.2 mol/L (M = 40). Concentration in g/L?

  1. 8 g/L
  2. 0.005 g/L
  3. 200 g/L
Show the answer

8 g/L

g/L = mol/L x molar mass = 0.2 x 40 = 8 g/L.

Other Chemistry topics

All of Leaving Cert Chemistry