Lesson Plan

• Apply the mole concept to convert between mass, moles, and number of particles.
• Calculate stoichiometric reacting masses and identify the limiting reactant in a chemical equation.
• Determine gas volumes at r.t.p. from mole quantities.
• Compute solution concentrations by mass and by molarity and perform dilution calculations.

• Projector or interactive whiteboard
• Printed worksheets with practice problems
• Calculators (or classroom computers)
• Periodic‑table handouts
• Sample chemical‑equation cards
• Gas‑syringe or virtual gas‑volume simulation (optional)

Start with a quick recall: what does one mole represent and why is Avogadro’s number important? Connect this to the previous lesson on atomic structure and molar mass. Explain that by the end of the lesson students will be able to calculate reacting masses, gas volumes and solution concentrations accurately.

1. Do‑now (5') – short questions on Avogadro’s constant and molar mass (checking prior knowledge).
2. Mini‑lecture (10') – review mass‑mole‑particle relationships and introduce stoichiometric calculations with balanced equations.
3. Guided practice (15') – convert given masses to moles, use mole ratios to find the limiting reactant, and back‑convert to mass.
4. Gas‑volume activity (10') – calculate volumes at r.t.p. using V = n × 24.0 dm³; work in pairs.
5. Solution‑concentration task (10') – determine mass of solute for a target molarity and perform a dilution using c₁V₁ = c₂V₂.
6. Quick check (5') – exit‑ticket with three short problems covering each sub‑topic (formative assessment).

Recap the four‑step pathway from mass to moles to stoichiometric ratios to product mass or volume, and the parallel steps for solution calculations. Collect the exit tickets to gauge understanding, and assign homework: a set of stoichiometry problems that include limiting‑reactant identification, gas‑volume calculations, and preparing a solution of a given concentration.