Chemistry · Grade 12

The Mole Concept

CAPE Unit 1

A complete Mole Concept module aligned to the supplied Unit 1 objectives and supporting notes, exercises and practical sheets.
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Course learning objectives

  • Objectives 3.1–3.9 from the supplied Mole Concept Unit 1 objectives sheet.
CAPE-U1-M1-MOLE

The Mole Concept

Grade 12 CAPE Unit 1 module: six 80-minute theory/problem-solving lessons plus two 80-minute practical lessons on acid-base and thermometric titration.

Download this module for offline use
MOLE-01 · The Mole, Avogadro's Constant and Molar Mass9 content · 2 resources
Introduces amount of substance, Avogadro's constant, molar mass and conversions among mass, moles and particles.

Lesson objectives

  • 3.2 Define the mole.
  • 3.3 Define molar mass.
  • Use Avogadro's constant to convert between amount and number of particles.

Syllabus objectives covered

  • 3.2 — Define the mole.
  • 3.3 — Define the term molar mass.

Starter: How many particles?

A laboratory sample contains an enormous number of particles. Discuss why chemists need a counting unit larger than a single atom or molecule.

The mole and Avogadro's constant

A mole is an amount of substance containing the same number of elementary particles as there are carbon atoms in 12.00000 g of carbon-12. The supplied notes use 6.02 × 1023 particles per mole as Avogadro's number.

Number of particles = number of moles × Avogadro's constant.

Particles and moles

N=nNAN=nN_A

Molar mass

The mass of one mole is the molar mass, measured in g mol−1. Its numerical value corresponds to the relative atomic, molecular or formula mass, but molar mass has units.

Mass–mole relationship

m=nMm=nM

Worked example

For 2.5 g of CO2, first find moles using n = m/M, then multiply by 6.02 × 1023 to obtain the number of molecules. This mirrors the approach required in the supplied Avogadro-number exercise.

Match the mole quantities

Drag each card into the correct category.
Amount (mol)
Molar mass (g mol⁻¹)
Number of particles

Mole relationship map

Drag each label to the numbered target that represents the correct idea.
Mole relationship map
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Lesson 1 Check

Answer all questions, then check your responses.
1. Which statement best defines one mole?
2. What is the unit of molar mass?
3. How many particles are in 0.50 mol?
4. Which expression gives moles from mass?
5. What is the molar mass of CO₂ using C=12 and O=16?

Resources

📄
CAPE Unit 1 Mole Concept ObjectivesSyllabus · PDF
Specific objectives and explanatory notes for the module. · Use this sheet to track the syllabus objectives addressed in the module.
Required
📄
Amount of Substance NotesNotes · PDF
Reference notes covering the mole, reacting masses, solutions, gases and formulae. · Read the sections on the mole and molar mass before completing the lesson activities.
Required
MOLE-02 · Balanced Equations, Mole Ratios and Reacting Masses7 content · 1 resources
Develops stoichiometric reasoning using balanced molecular/ionic equations and reacting-mass calculations.

Lesson objectives

  • 3.4 Write balanced molecular and ionic equations.
  • 3.5 Perform reacting-mass calculations.
  • 3.6 Apply mole ratios from balanced equations to molecular and ionic equations.

Syllabus objectives covered

  • 3.4 — Write balanced molecular and ionic equations.
  • 3.5 — Perform calculations based on the mole concept, relating masses, gas volumes, solution volumes and concentrations.
  • 3.6 — Apply the mole concept to molecular and ionic equations.

Starter: Coefficients are mole ratios

In a balanced equation, coefficients show the ratio in which species react. They do not represent masses. Explain why masses must first be converted to moles.

Balanced equations and stoichiometric ratios

Chemical equations conserve atoms. Reaction coefficients provide simple whole-number mole ratios. For reacting-mass calculations: balance the equation → convert the known quantity to moles → use the coefficient ratio → convert the required moles to the requested quantity.

Reacting masses model

For 3CuO + 2Al → Al2O3 + 3Cu, the supplied notes convert 10 g CuO to moles, apply the 3:2 ratio to Al and the 3:1 ratio to Al2O3, then convert back to mass.

Ionic equations

In aqueous reactions, spectator ions remain unchanged and are omitted from the ionic equation. For a strong acid–strong alkali reaction, the supplied notes reduce the molecular equation to H+(aq) + OH−(aq) → H2O(l).

Sort the stoichiometry steps

Drag each card into the correct category.
Before mole ratio
Use the equation
After mole ratio

Stoichiometry pathway

Drag each label to the numbered target that represents the correct idea.
Stoichiometry pathway
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Lesson 2 Check

Answer all questions, then check your responses.
1. In 2H₂ + O₂ → 2H₂O, the mole ratio H₂:O₂ is
2. Why are masses converted to moles before using an equation ratio?
3. Which ions are omitted from an ionic equation?
4. For H⁺ + OH⁻ → H₂O, the H⁺:OH⁻ mole ratio is
5. After finding required moles of a solid product, which relationship gives its mass?

Resources

📄
Avogadro's Number and Reacting Masses ExercisePractice · PDF
Practice on particles and stoichiometric reacting masses. · Complete the reacting-mass questions after the worked examples.
Required
MOLE-03 · Solutions, Concentration and Titration Calculations9 content · 1 resources
Connects the mole concept to solution concentration and quantitative titration calculations.

Lesson objectives

  • 3.5 Relate moles to solution volumes and concentrations.
  • 3.8 Explain the quantitative basis of titrimetric analysis.
  • 3.9 Use titration information to calculate mole ratios and molar/mass concentration.

Syllabus objectives covered

  • 3.5 — Perform calculations based on the mole concept, relating masses, gas volumes, solution volumes and concentrations.
  • 3.8 — Perform titrimetric analyses.
  • 3.9 — Use titrimetric results to calculate mole ratios, molar concentration and mass concentration.

Starter: Concentration and volume

25.0 cm³ is not 25.0 dm³. Before using n = CV, identify the volume unit required and convert cm³ to dm³.

Solutions and molarity

Concentration in mol dm−3 relates amount and solution volume through n = CV, where V must be in dm3. If a concentration is given in g dm−3, it can be related to molar concentration using molar mass.

Moles in solution

n=CVn=CV

Mass and molar concentration

Cg=CmMC_{g}=C_{m}M

Titration calculations

Volumetric analysis compares reacting solution volumes. The supplied notes emphasize converting each measured quantity to moles, using the balanced-equation mole ratio, then determining the unknown concentration.

Acid–base example

For H2SO4 + 2NaOH → Na2SO4 + 2H2O, calculate moles of the known NaOH from C×V, use the 2:1 ratio, then divide acid moles by acid volume in dm³.

Sort titration quantities

Drag each card into the correct category.
Measured directly
Calculated
Chemical relationship

Titration calculation flow

Drag each label to the numbered target that represents the correct idea.
Titration calculation flow
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Lesson 3 Check

Answer all questions, then check your responses.
1. 25.0 cm³ equals
2. Which equation relates moles, concentration and volume?
3. In a titration calculation, the reacting ratio comes from
4. If n and V are known, concentration is
5. A solution concentration in g dm⁻³ can be found from molar concentration by

Resources

📄
Titration CalculationsPractice · PDF
Seven titration calculation problems with answers. · Use selected questions for guided and independent practice.
Required