2.1.3
Amount of Substance
This section covers the mole and the Avogadro constant, molar mass and molar gas volume, empirical and molecular formulae, hydrated salts, calculations with masses, gas volumes and solutions, the ideal gas equation, percentage yield and atom economy.
These pages cover the mole, formulae, every calculation type, hydrated salts and measuring techniques.
Revision Notes
6 revision notes, in the order the specification teaches them.
Atoms, Elements and Molecules
Atoms, elements, ions and molecules, relative masses, molar mass, the mole and the Avogadro constant (2.1.3 (a)).
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Mole Calculations
Comparing masses, calculations involving moles, reacting masses, percentage yield and atom economy (2.1.3 (e), (g), (h), (j)).
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Empirical and Molecular Formulae
Empirical formulae from composition by mass and molecular formulae from Mᵣ (2.1.3 (b), (c)).
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Calculations with Solutions and Gases
Molar gas volume, the ideal gas equation and concentrations of solutions (2.1.3 (a)(v), (e), (f)).
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Hydrated Salts and Water of Crystallisation
Anhydrous and hydrated salts, and finding x in a hydrated salt from percentage composition or heating to constant mass (2.1.3 (d)).
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Measuring Mass, Volume and Gas Volume
Weighing by difference, pipettes, burettes and volumetric flasks, collecting gases, and percentage uncertainty (2.1.3 (i)).
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Moles and Masses Map
OCR A Level Chemistry A · 2.1.3 Amount of substance · Moles and masses
Moles and masses on one A4 page: amount of substance, the Avogadro constant, molar mass, reacting masses, yield, atom economy and sustainability.
Formulae and Hydrated Salts Map
OCR A Level Chemistry A · 2.1.3 Amount of substance · Formulae and hydrated salts
Formulae and hydrated salts on one A4 page: empirical formulae, awkward ratios, molecular formulae, combustion analysis and hydrated salts.
Solutions and Gases Map
OCR A Level Chemistry A · 2.1.3 Amount of substance · Solutions and gases
Solutions and gases on one A4 page: concentration, standard solutions, molar gas volume, pV = nRT and measuring mass, volumes and gas volumes.
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2.1.3
- a (ii)
explanation and use of the term mole (symbol 'mol'), as the unit for amount of substance
Revise - a (iii)
explanation and use of the term the Avogadro constant, NA (the number of particles per mole, 6.02 × 10^23 mol–1)
Revise - b (i)
use of the term empirical formula (the simplest whole number ratio of atoms of each element present in a compound)
Revise - b (ii)
use of the term molecular formula (the number and type of atoms of each element in a molecule)
Revise - c iii
calculations of molecular formulae from composition by mass or percentage compositions by mass and relative molecular mass
Revise - e (iii)
calculations, using amount of substance in mol, involving solution volume and concentration
Revise - i i
the techniques and procedures required during experiments requiring the measurement of mass
Revise - i ii
the techniques and procedures required during experiments requiring the measurement of volumes of solutions
Revise - i iii
the techniques and procedures required during experiments requiring the measurement of gas volumes
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