Safety boundary
Use paper models, supplied data, and approved simulations only. No unsupervised reactive mixtures are required.
Explicit chemistry instruction
Stoichiometry links three scales: particles, moles, and measured mass. The mole is the bridge that lets chemists move between them.
A reliable solution identifies the starting unit, desired unit, and conversion chain before arithmetic.
Friday synthesis should include at least one correction showing where a unit, coefficient, or formula error was repaired.
Vocabulary: conversion chain; scale bridge; coefficient; molar mass; correction.
Worked example
A grams-to-particles problem may require grams→moles using molar mass, then moles→particles using Avogadro's constant.
Guided question
Design the shortest valid conversion chain from grams of reactant to molecules of product.
Independent work
- Solve one particle↔mole problem.
- Solve one mass↔mole problem.
- Solve one multi-step stoichiometry problem.
- Record one corrected conversion error.
Spiral retrieval bridge
- From Week 14: read coefficients as mole ratios in a balanced equation.
- From Week 12: distinguish molarity from total solute amount.
- From Week 03: explain how particle-scale counts connect to macroscopic mass.
Misconception check
Dimensional analysis is not decoration; unit cancellation is part of the scientific logic.
Formative check
What should determine the order of conversion factors?
Reveal response
The starting unit and the target unit.
Mentor evidence conference
Ask Archaemenes to audit units, conversion factors, equation coefficients, and model assumptions.
Teacher guidance
Foundation: Use a conversion-roadmap template.
Core: Integrate all three scales.
Extended: Compare alternate conversion chains and defend the clearest one.