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Edexcel International A Level Chemistry

Mole Calculations

Mole calculations connect the symbolic equation to measurable quantities in the laboratory. These pages build from comparing masses and using the mole equation through to reacting mass calculations, percentage yield and atom economy.

Exam Unit
Unit 1
WCH11/01 – IAS
Specification Points
1.4 – 1.9
4 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.

A balance comparing one heavy atom with twelve light ones
1

Comparing Masses of Substances

Revise relative atomic mass, relative formula mass and how chemists compare the masses of particles and compounds.

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A heap of powder opening out into countless particles
2

Calculations involving Moles

Practise using amount of substance, mass and relative formula mass in the core mole calculation relationship.

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Two piles of reactant in a fixed ratio
3

Calculations using Reacting Masses

Use balanced equations and mole ratios to calculate the mass of reactants needed or products formed.

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A flask holding less product than the full amount
4

The Yield of a Reaction

Understand theoretical yield, actual yield and why percentage yield is often less than 100% in practical chemistry.

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A wanted molecule with a small waste fragment breaking away
5

Atom Economy

Revise how atom economy measures the proportion of reactant atoms converted into the desired product.

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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.

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Summary map · PDF

Basic Calculations Map

Edexcel International A Level Chemistry · Unit 1 · Topic 1C Basic Calculations

The whole section on one A4 page: relative masses, the mole, counting particles, reacting masses, yield, atom economy and formulae by experiment.

Download the map6 key ideas + an equations 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.

Self-assessment · 38 points

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1.1

  1. a

    know the term 'atom'

    Revise
  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

    Revise
  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

    Revise