Moles and masses
I can calculate mass of a substance or the number of moles it contains from data.
Moles and masses
I can calculate mass of a substance or the number of moles it contains from data.
Lesson details
Key learning points
- The number of particles (atoms, ions, molecules etc.) in one mole of a substance is always the same.
- The mass of one mole of a substance is equal to the relative mass of the substance measured in grams.
- Mathematical relationships are manipulated to process practical results, calculating the number of moles in a substance.
Common misconception
Pupils struggle to link a mole to number of particles.
Use real world examples of converting volumes / masses into number of particles so pupils become more comfortable converting between moles, number of particles particles and masses.
Keywords
Mole - 1 mole of a substance is 6.02 × 10²³ particles of it. The mass of a mole of a substance is its relative mass in grams.
Avogadro's constant - Avogadro's constant is the number of particles in one mole of a substance (6.02 × 10²³ mol⁻¹).
Relative formula mass - The relative formula mass (RFM or Mᵣ) of a substance is the sum of the relative atomic masses of all the atoms in its formula.
Equipment
balances, pennies, small beakers, water, dropping pipettes, paper towels, calculators
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).
Video
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Starter quiz
6 Questions
describes a reaction, indicating the reactants and products
shows the number of atoms of each element in a substance
number placed in front of a chemical formula to balance an equation
written slightly below and to the side of another character
indicates the physical state of substances in a reaction
4
9
19
20
11
23
Exit quiz
6 Questions
0.5 mol
1.0 mol
1.25 mol
1.5 mol
1.75 mol
2.5 mol