Topic: Stoichiometry- Mole and the Avogadro Constant
Lesson 1: The Mole and Avogadro Constant
| Section | Details |
|---|---|
| Objective | State that the mole (mol) is the unit of amount of substance and that one mole contains 6.02×10236.02 \times 10^{23} particles (Avogadro constant). |
| Activities | – Starter (5 mins): Show one mole of a substance (e.g., one mole of water = 18 g). Ask: “What makes this quantity special?” – Main (25 mins): 1. Define the mole and explain its relationship to particles. 2. Introduce the Avogadro constant and relate it to real-world quantities (e.g., one mole of NaCl contains 6.02×10236.02 \times 10^{23} formula units).- Plenary (10 mins): Students calculate the number of particles in one mole of H₂O and NaCl. |
| Resources | Mole models, periodic table, worksheets with practice questions. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Calculate the number of particles in 0.5 moles of CO₂ and 2 moles of NaOH. |
| Assessment | Worksheet: Define the mole and calculate the number of particles for given moles. |
| Past Paper Practice | IGCSE Chemistry 0620/41/M/J/20 Q5(a) – Understanding the mole and Avogadro constant. |
Lesson 2: Calculations Using Moles
| Section | Details |
|---|---|
| Objective | Use the relationship Amount of substance (mol)=mass (g)molar mass (g/mol)\text{Amount of substance (mol)} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} to calculate: (a) amount of substance, (b) mass, (c) molar mass, (d) relative atomic/molecular mass, (e) number of particles using the Avogadro constant. |
| Activities | – Starter (5 mins): Show a sample of a substance (e.g., NaCl) and ask: “How can we find the number of moles?” – Main (25 mins): 1. Introduce the formula and solve examples for each type of calculation (mass, molar mass, relative atomic/molecular mass). 2. Practice converting between moles and particles using the Avogadro constant. – Plenary (10 mins): Students solve a set of problems involving the formula. |
| Resources | Periodic table, calculators, worksheets with guided examples. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Calculate the mass, moles, and number of particles for 3 substances provided. |
| Assessment | Quiz: Solve mole-related problems using the formula. |
| Past Paper Practice | IGCSE Chemistry 0620/41/O/N/21 Q5(b) – Calculating moles, mass, and number of particles. |
Lesson 3: Molar Gas Volume and Concentration
| Section | Details |
|---|---|
| Objective | Use the molar gas volume (24 dm³ at r.t.p.) for gas calculations and state that concentration can be measured in g/dm3\text{g/dm}^3 or mol/dm3\text{mol/dm}^3. |
| Activities | – Starter (5 mins): Demonstrate the volume of a gas by inflating a balloon and relate it to moles. – Main (25 mins): 1. Define molar gas volume and use it to calculate gas volumes at r.t.p. (e.g., one mole of CO₂ = 24 dm³). 2. Introduce concentration units g/dm3\text{g/dm}^3 and mol/dm3\text{mol/dm}^3 and practice conversions. – Plenary (10 mins): Students solve questions involving gas volumes and concentration conversions. |
| Resources | Balloons, volumetric flasks, worksheets with gas and concentration problems. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Calculate the volume of gas produced in 3 given reactions at r.t.p. |
| Assessment | Worksheet: Solve problems involving gas volumes and solution concentrations. |
| Past Paper Practice | IGCSE Chemistry 0620/41/M/J/19 Q4(c) – Using molar gas volume in calculations. |
Lesson 4: Stoichiometry and Titration
| Section | Details |
|---|---|
| Objective | Calculate stoichiometric reacting masses, limiting reactants, and concentrations of solutions. Use experimental data to calculate concentrations via titration. |
| Activities | – Starter (5 mins): Explain the concept of limiting reactants using a practical analogy (e.g., sandwiches with fixed bread and filling). – Main (25 mins): 1. Solve problems involving stoichiometric calculations, including limiting reactants. 2. Introduce titration experiments and demonstrate the procedure. – Plenary (10 mins): Students analyze a titration data table to calculate concentration. |
| Resources | Titration apparatus, volumetric flasks, worksheets with stoichiometry problems. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Solve titration problems involving acid-base reactions. |
| Assessment | Quiz: Solve stoichiometry and titration-based problems. |
| Past Paper Practice | IGCSE Chemistry 0620/41/O/N/20 Q6(a) – Calculating stoichiometric masses and concentrations. |
Lesson 5: Empirical and Molecular Formulae, Percentage Yield, and Purity
| Section | Details |
|---|---|
| Objective | Calculate empirical/molecular formulae, percentage yield, percentage composition, and percentage purity. |
| Activities | – Starter (5 mins): Explain why yields in chemical reactions may not reach 100%. – Main (25 mins): 1. Define and solve problems for empirical and molecular formulae. 2. Introduce the formulas for percentage yield and purity, and practice using data tables. 3. Solve real-world problems (e.g., purity of a metal in an ore). – Plenary (10 mins): Students solve a summary problem involving multiple calculations (e.g., yield and purity). |
| Resources | Worksheets with experimental data, calculators, molecular diagrams. |
| Time | 40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary). |
| Homework | Solve problems involving percentage yield and purity for three reactions. |
| Assessment | Worksheet: Calculate empirical formulae, yield, and purity from provided data. |
| Past Paper Practice | IGCSE Chemistry 0620/41/M/J/20 Q6(b) – Percentage yield and purity calculations. |
Notes for Teachers:
- Use real-world analogies to explain abstract concepts like moles and Avogadro constant.
- Incorporate experiments (e.g., titration) to connect theoretical calculations with practical applications.
- Provide step-by-step guides for multi-step calculations to support students.
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