Canonical lesson CHEMISTRY20-U4-L15 · outcome 20-D2.5k · depth CURRICULUM_BASELINE

Unit D: Quantitative Relationships in Chemical Changes - outcome 20-D2.5k

• Course: CHEMISTRY20 (SCN2796)
• Lesson ID: CHEMISTRY20-U4-L15
• Official outcome: 20-D2.5k (KNOWLEDGE)
• Object type: canonical lesson (not a bootcamp session)
• Source: Alberta Chemistry 20 Program of Studies (2007, updated 2014)

Official outcome text

draw and interpret titration curves, using data from titration experiments involving strong monoprotic acids and strong monoprotic bases

Learning intention

Meet 20-D2.5k 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

Strong monoprotic acid vs strong monoprotic base: pH starts low (acid in flask), rises slowly, then jumps through pH 7 at equivalence, then levels high. The curve is pH vs volume of titrant. Equivalence is the steep inflection. Use a provided dataset if no burette day.

Worked example

25.0 mL of 0.100 mol/L HCl titrated with 0.100 mol/L NaOH: equivalence at 25.0 mL, pH 7 at 25 °C. Before: buffer-like slow rise still acidic; after: determined by excess OH−.

Guided practice

1. Sketch pH vs V for 20.0 mL of 0.100 mol/L HCl with 0.100 mol/L NaOH. Mark equivalence volume. Do not copy 25.0 mL only.
2. Near-miss: calling the phenolphthalein colour change the equivalence by definition. Distinguish end point.

Independent practice

1. Regions: excess acid, equivalence, excess base.
2. Two sentences: strong-strong, pH 7 at 25 °C at equivalence.
3. School titration or provided dataset - no home burettes.

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

Drawing a weak-acid buffer shape for HCl/NaOH, or tasting to find the end point.

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

Curve sketch with equivalence labelled for a stated volume.

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

AI Tutor / human tutor

Ground on 20-D2.5k. 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.