THE DMS ONLINE SCHOOL
Grade/Class: Grade 11 Number of Pupils in Class: 45 Date: 2026-05-11 Duration: 79 minutes
Name of Teacher: MR MASUMBA
Subject: Chemistry Topic: THE MOLE CONCEPT Subtopic: The mole Rationale: This is lesson number one in the THE MOLE CONCEPT study series. The mole is an important concept because it helps learners in Zambia relate particles that cannot be seen directly, such as atoms, ions and molecules, to measurable quantities such as mass and gas volume. This knowledge is useful in school laboratory calculations, agriculture, mining, manufacturing and health-related sciences where accurate measurement of substances is essential. The lesson will use the Learner-Centered Approach through Discussion Method, Demonstration Method, Practical Work Method and Question & Answer Method so that learners actively construct meaning, interpret charts, apply formulas and solve mole problems with precision. Specific Outcome(s): By the end of the lesson, learners should be able to: • Describe a mole. • Determine the physical masses (m) of any substance using the molar mass (Mr) and the physical volume (v) of any gas at r.t.p and vice versa. Prerequisite Knowledge: • Meaning of atoms, molecules, ions and electrons • Difference between relative atomic mass and relative molecular mass • Basic algebraic rearrangement of formulas • Units of mass in grams and volume in dm3 • Reading and interpreting simple chemical formulae such as H2O, CO2 and O2 References: • Chemistry Pupil's Textbook Grade 11, pg. 42–47 • Senior Secondary Chemistry Learner's Book, pg. 88–93 • Zambia Senior Secondary School Chemistry Syllabus, pg. 29–30 Knowledge: As number or quantities of particles e.g. atoms, ions, molecules, electrons equivalent to 6.02 × 1023 (Avogadro's constant); Apply n = mMr and n = vVm where n = number of moles Skills: • Mathematical problem-solving • Chemical calculations • Formula application • Stoichiometric analysis Values: • Mathematical precision • Logical thinking • Systematic approach • Attention to detail Teaching / Learning Aids: Drawn / Prepared Aids (Manila Paper / Cardboard): 1. Manila chart: Large definition chart titled “One Mole” showing four labelled boxes: “atoms”, “molecules”, “ions”, “electrons”, each linked by arrows to “6.02 × 1023 particles”, with examples “1 mole of C atoms”, “1 mole of H2O molecules”, “1 mole of Na+ ions”, and “1 mole of electrons”. 2. Manila chart: Formula chart titled “Mole Relationships” showing the labelled formulas n = mMr and n = vVm, with labels “number of moles”, “mass in g”, “molar mass in g mol-1”, “gas volume in dm3”, and “molar volume at r.t.p = 24 dm3 mol-1”. 3. Cardboard chart: Worked examples table with three labelled columns “Question”, “Substitution”, “Answer” and three rows: “Find moles in 18 g H2O”, “Find mass of 0.5 mol CO2”, and “Find moles in 48 dm3 O2 at r.t.p”. 4. Manila chart: Comparison chart titled “Mass–Mole–Volume Conversion” showing three linked panels with arrows: “mass to moles”, “moles to mass”, and “volume to moles / moles to volume”, each panel containing one short rule and one example heading. Alternative Materials: • Whiteboard drawings of the same formulas and worked examples • Projected slides of the four prepared charts METHODOLOGIES, STRATEGIES AND APPROACHES: Approach: Learner-Centered Approach Method: • Question & Answer Method — Introduction, Step 4 • Demonstration Method — Development Step 1 • Discussion Method — Step 2 • Practical Work Method — Step 3 Strategy: • Brainstorming — Introduction • Use of Charts/Diagrams — Introduction, Development Step 1, Step 2 • Guided Questioning — Development Step 1, Step 4 • Think-Pair-Share — Step 2 • Group Work — Step 3 Lesson Implementation: [TABLE_START] Stage|Teaching Methods|Teacher's Activities|Learner's Activities|Learning Points Introduction - 10 min|Question & Answer Method|Teacher greets learners, introduces the subtopic, and displays Manila chart 1 — “One Mole”. Teacher asks: “According to this chart, how many particles are in one mole?” and “Which four particle types are shown on the chart?”|Learners study Manila chart 1 and answer: “One mole contains 6.02 × 1023 particles.” They identify all four particle types shown: atoms, molecules, ions and electrons.|A mole is the amount of substance containing 6.02 × 1023 particles. Particle examples on the chart: 1 mole of C atoms, 1 mole of H2O molecules, 1 mole of Na+ ions, 1 mole of electrons. Development Step 1 - 20 min|Demonstration Method|Teacher displays Manila chart 2 — “Mole Relationships” and Cardboard chart 3 — worked examples table. Teacher demonstrates how to use n = mMr for 18 g H2O and n = vVm for 48 dm3 O2 at r.t.p, pointing to the formula labels and substitution column.|Learners observe the steps on Manila chart 2 and Cardboard chart 3, then write the demonstrated substitutions and answers in their exercise books. They note that r.t.p molar volume on the chart is 24 dm3 mol-1.|1. For H2O, Mr = 18. 2. n = 1818 = 1 mol. 3. At r.t.p, Vm = 24 dm3 mol-1. 4. For O2, n = 4824 = 2 mol. Step 2 - 15 min|Discussion Method|Teacher displays Manila chart 4 — “Mass–Mole–Volume Conversion” and asks pairs to discuss: “Which panel is used for mass to moles, which panel is used for moles to mass, and which panel is used for volume to moles and moles to volume?” Teacher then asks: “In the volume to moles / moles to volume panel, when is 24 dm3 mol-1 used?”|Learners discuss in pairs and share: “The mass to moles panel is used for mass to moles, the moles to mass panel is used for moles to mass, and the volume to moles / moles to volume panel is used for volume to moles and moles to volume.” They then answer: “24 dm3 mol-1 is used for gases at r.t.p.”|Conversion rules: n = mMr, m = nMr, n = v24, and v = 24n at r.t.p. Example of correct learner output: “0.5 mol CO2 uses the moles to mass panel.” Step 3 - 24 min|Practical Work Method|Teacher directs learners into groups of 5 and refers them to Cardboard chart 3 and Manila chart 4. Teacher gives the group tasks: “Using the row ‘Find mass of 0.5 mol CO2’, state the formula, substitution and answer.” and “Using the volume to moles / moles to volume panel on chart 4, calculate the volume of 3 mol O2 at r.t.p with formula, substitution and final answer.”|Learners work in groups of 5 and use Cardboard chart 3 to state for ‘Find mass of 0.5 mol CO2’ the formula, substitution and answer shown on the chart. They then use the volume to moles / moles to volume panel on Manila chart 4 to calculate the volume of 3 mol O2 at r.t.p, writing the formula, substitution and final answer for presentation.|Group task: 1. Find mass of 0.5 mol CO2. 2. Find volume of 3 mol O2 at r.t.p. Needed formulas: m = nMr and v = 24n. Guiding framework: identify formula, find Mr, substitute correctly, state unit. Step 4 - 10 min|Question & Answer Method|Teacher invites group feedback and asks: “What is a mole?” “What is the mass of 0.5 mol CO2?” and “What is the volume of 3 mol O2 at r.t.p?” Teacher confirms answers, corrects errors, and gives homework: “Calculate the number of moles in 36 g H2O and the volume of 0.25 mol N2 at r.t.p.”|Learners answer: “A mole is the amount of substance containing 6.02 × 1023 particles.” “The mass of 0.5 mol CO2 is 22 g.” “The volume of 3 mol O2 at r.t.p is 72 dm3.” Learners record the homework exactly as given.|Summary: a mole links particles to measurable mass and gas volume. Worked solutions: for CO2, Mr = 44, so m = 0.5 × 44 = 22 g; for O2, v = 24 × 3 = 72 dm3. Homework: calculate moles in 36 g H2O and volume of 0.25 mol N2 at r.t.p. 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