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Edexcel International A Level Chemistry

Topic 1
Formulae, Equations
& Amount of Substance

Topic 1 builds the calculation and chemical language foundation for A Level Chemistry. It covers atoms, elements, ions, molecules, compounds, empirical formulae, molecular formulae, balanced equations, reacting masses, solution concentrations, gas volumes, percentage yield and atom economy.

Exam Unit
Unit 1
WCH11/01 – IAS
Specification Points
1.1 – 1.12
12 points covered
Sub-topics
5 lessons
Revision notes available
Exam Board
Edexcel IAL
Pearson International

Revision Notes

5 revision notes, in the order the specification teaches them.

Single atoms beside a molecule of an element and a compound
1

Atoms, Elements and Molecules

Key definitions including atom, element, ion, molecule, compound, empirical formula and molecular formula.

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A level balance with the same atoms in each pan
2

Equations and Reaction Types

Balanced equations, ionic equations, state symbols, acid reactions and precipitation reactions.

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A heap of powder opening out into countless particles
3

Mole Calculations

The mole, Avogadro constant, molar mass, reacting masses, percentage yield and atom economy.

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A whole molecule beside its simplest repeating unit
4

Empirical and Molecular Formulae

Using experimental data, percentage composition and molar mass to calculate empirical and molecular formulae.

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Two beakers, one dilute and one concentrated
5

Calculations with Solutions and Gases

Concentration in mol dm-3 and g dm-3, gas volumes, molar volume and the ideal gas equation.

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Summary Map

Download, print and revise the key facts of this topic at a glance.

Summary map

Download, print and revise the key facts of this topic at a glance.

Illustration of a summary map: compounds joined by reaction arrows
Summary map · PDF

Atoms, Elements and Molecules Map

Edexcel International A Level Chemistry · Unit 1 · Topic 1A Atoms, Elements and Molecules

The whole section on one A4 page: atoms, elements, molecules, compounds and mixtures, ions, ion charges and the formulae of ionic compounds.

Download the map6 key ideas + a polyatomic ion table · A4 portrait · print ready

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Virtual Lessons

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8 exam-style multiple-choice papers, MCQ (A) to (H): 170 questions on Topic 1 Formulae, Equations and Amount of Substance, written the way the exam asks them.

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Specification

Every specification point in this topic, in the exam board's own words. Rate how confident you are with each one.

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1.1

  1. a

    know the term 'atom'

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  2. b

    know the term 'element'

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  3. c

    know the term 'ion'

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  4. d

    know the term 'molecule'

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  5. e

    know the term 'compound'

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  6. f

    know the term 'empirical formula'

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  7. g

    know the term 'molecular formula'

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1.2

  1. a

    know that the mole (mol) is the unit for the amount of a substance

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  2. b

    be able to perform calculations using the Avogadro constant L (6.02 x 10^23 mol-1)

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1.3

  1. a

    write balanced full equations, including state symbols, for chemical reactions

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  2. b

    write balanced ionic equations, including state symbols, for chemical reactions

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1.4

  1. i

    understand the term 'relative atomic mass'

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  2. ii a

    understand the term 'relative molecular mass', including calculating this value from relative atomic masses

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  3. ii b

    understand the term 'relative formula mass', including calculating this value from relative atomic masses

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  4. ii c

    know that the term 'relative formula mass' should be used for compounds with giant structures

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  5. iii

    understand the term 'molar mass'

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  6. iv

    understand the terms: parts per million (ppm), including gases in the atmosphere

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1.5

  1. a

    calculate the concentration of a solution in mol dm−3

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  2. b

    calculate the concentration of a solution in g dm−3

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  3. c

    know that titration calculations are not required at this stage

1.6

  1. a

    be able to use experimental data to calculate empirical formulae

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  2. b

    be able to use experimental data to calculate molecular formulae

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1.7

  1. a

    be able to use chemical equations to calculate reacting masses using the concepts of amount of substance and molar mass

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  2. b

    be able to use reacting masses to calculate chemical quantities from equations using the concepts of amount of substance and molar mass

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1.8

  1. i

    be able to use chemical equations to calculate volumes of gases and vice versa, using: the concepts of amount of substance

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  2. ii

    be able to use chemical equations to calculate volumes of gases and vice versa, using: the molar volume of gases

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  3. iii

    be able to use chemical equations to calculate volumes of gases and vice versa, using: the expression pV = nRT for gases and volatile liquids

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1.9

  1. a

    be able to calculate percentage yields in laboratory processes using chemical equations and experimental results

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  2. b

    be able to calculate percentage yields in industrial processes using chemical equations and experimental results

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  3. c

    be able to calculate percentage atom economies by mass in laboratory processes using chemical equations and experimental results

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  4. d

    be able to calculate percentage atom economies by mass in industrial processes using chemical equations and experimental results

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  5. e

    know that atom economy = molar mass of the desired product × 100% / sum of the molar masses of all products

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1.10

  1. a

    be able to determine a formula by experiment, including evaluation of the data

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  2. b

    be able to confirm an equation by experiment, including evaluation of the data

1.11

  1. 1.11

    CORE PRACTICAL 1 Measurement of the molar volume of a gas.

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1.12

  1. i

    be able to relate ionic and full equations, with state symbols, to observations from simple test-tube experiments, to include: displacement reactions

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  2. ii

    be able to relate ionic and full equations, with state symbols, to observations from simple test-tube experiments, to include: typical reactions of acids

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  3. iii

    be able to relate ionic and full equations, with state symbols, to observations from simple test-tube experiments, to include: precipitation reactions

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