S1.4 Counting particles by mass: The mole
14 revision questions with answers for S1.4 Counting particles by mass: The mole, marked SL. Read them here, or play the set as a class game on the projector. Free to host, and students join with a code.
Number of particles in one mole of a substance?
- 6.02 × 10²²
- 3.01 × 10²³
- 1.00 × 10²³
- 6.02 × 10²³Right answer
What this set covers
The mole as a counting unit: Avogadro's number, molar mass, empirical and molecular formulae, percentage composition, and solution concentration including dilution from a stock solution.
- Common mix-up
- Students often mix up relative atomic mass and molar mass: one is a unitless ratio against carbon-12, the other is the mass of one mole in g mol⁻¹.
- Revision tip
- Redo the dilution and concentration questions by writing amount, volume in dm³ and concentration as three linked quantities, converting cm³ before you calculate.
All 14 questions and answers
Number of particles in one mole of a substance?
Answer: 6.02 × 10²³
Mass of one mole of a substance, in g mol⁻¹?
Answer: Molar mass
Weighted mean mass of an element's atoms compared with one-twelfth of a carbon-12 atom?
Answer: Relative atomic mass
Relative formula mass of H₂SO₄ (Ar: H 1, S 32, O 16)?
Answer: 98
Amount of water in 36 g of water (Mr = 18)?
Answer: 2.0 mol
Mass of 0.25 mol of CaCO₃ (Mr = 100)?
Answer: 25 g
Number of oxygen atoms in 1 mol of CO₂?
Answer: 1.20 × 10²⁴
Empirical formula of C₆H₁₂O₆?
Answer: CH₂O
A hydrocarbon has empirical formula CH₂ and Mr = 56. Its molecular formula?
Answer: C₄H₈
Percentage by mass of carbon in CH₄ (Mr = 16)?
Answer: 75%
Concentration when 0.50 mol of NaCl makes 250 cm³ of solution?
Answer: 2.0 mol dm⁻³
Amount of solute in 100 cm³ of 0.20 mol dm⁻³ solution?
Answer: 0.020 mol
Volume of 1.0 mol dm⁻³ stock needed for 500 cm³ of 0.20 mol dm⁻³ solution?
Answer: 100 cm³
Equal volumes of gases at the same temperature and pressure contain equal…?
Answer: Numbers of particles
Play it as a class game
Play this set opens it in splycr, where you can host it for your class straight away. Hosting needs no account: put the room code on the projector, and students join from a phone with the code and their first name. Each question plays as multiple choice, and the three wrong options were written for that question.