Canonical lesson CHEMISTRY20-U4-L02 · outcome 20-D1.2k · depth CURRICULUM_BASELINE

Unit D: Quantitative Relationships in Chemical Changes - outcome 20-D1.2k

• Course: CHEMISTRY20 (SCN2796)
• Lesson ID: CHEMISTRY20-U4-L02
• Official outcome: 20-D1.2k (KNOWLEDGE)
• Object type: canonical lesson (not a bootcamp session)
• Source: Alberta Chemistry 20 Program of Studies (2007, updated 2014)

Official outcome text

recall the balancing of chemical equations in terms of atoms, molecules and moles

Learning intention

Meet 20-D1.2k with instruction, practice, and a check. The 10-session bootcamp does not replace this lesson.

Success criteria

1. Restate the outcome in classroom language without swapping in a different unit’s template.
2. Complete the worked-style task for this outcome.
3. Name the lab setting (classroom-supervised / teacher demo / dataset or simulation / forbidden).

Teaching

A balanced equation conserves atoms; coefficients are mole ratios (and molecule ratios) as well as particle ratios. 2 H2 + O2 → 2 H2O means 2 mol H2 : 1 mol O2 : 2 mol H2O. Do not change subscripts to balance.

Worked example

Balance Fe + O2 → Fe2O3 as 4 Fe + 3 O2 → 2 Fe2O3. Interpretation: 4 mol Fe react with 3 mol O2. Changing Fe2O3 to FeO to “make it easier” is illegal.

Guided practice

1. Balance C2H6 + O2 → CO2 + H2O (complete combustion). Do not copy 4 Fe + 3 O2.
2. Near-miss: changing Fe2O3 to FeO to make balancing easier. Mark it illegal.

Independent practice

1. Interpret coefficients as moles for the balanced ethane equation.
2. Two sentences: atoms conserved; coefficients change counts of molecules.
3. Lowest whole-number coefficients.

Diagram / whiteboard

Approved diagram id chem20-stoich-mole-map - Mole map stoichiometry flow. Tutor may open the course whiteboard and display this id. Do not invent hazardous procedures on the board.

Checks for understanding

Use the formative evidence below as the exit check for this outcome. Correct the misconception named in this lesson before praising.

Misconception to repair

Changing subscripts, or reading coefficients as grams directly.

Safety and lab register

Setting: stoichiometry on balanced equations and provided mass/volume data. Live combustion or precipitation is teacher demo or school lab SOP only - never a home task. Titration (if run) is school burette, dilute reagents, goggles; otherwise use the provided titration-curve dataset. Forbidden: student-run flames, concentrating acids, tutor-invented yields labs. AI Tutor must not invent procedures.

Alberta Poison Control if a real exposure is occurring: 1-844-764-7669. The AI Tutor is not a poison centre.

Formative evidence

Balanced Fe + O2 → Fe2O3 with mole interpretation.

This is not a diploma. Mastery needs instruction + activity + check.

AI Tutor / human tutor

Ground on 20-D1.2k. No false praise. No invented procedures. No silent skip to a different unit. Human tutor if the student describes mixing bleach, tasting, or flames.

Provenance

Official POS wording from ALBERTA_SENIOR_HIGH_OFFICIAL_OUTCOMES.csv. Pack lesson written to replace Wave-4 contaminated canonical markdown.