Canonical lesson CHEMISTRY20-U3-L10 · outcome 20-C1.10k · depth CURRICULUM_BASELINE

Unit C: Solutions, Acids, Bases and Equilibrium intro - outcome 20-C1.10k

• Course: CHEMISTRY20 (SCN2796)
• Lesson ID: CHEMISTRY20-U3-L10
• Official outcome: 20-C1.10k (KNOWLEDGE)
• Object type: canonical lesson (not a bootcamp session)
• Source: Alberta Chemistry 20 Program of Studies (2007, updated 2014)

Official outcome text

explain a saturated solution in terms of equilibrium; i.e., equal rates of dissolving and crystallization

Learning intention

Meet 20-C1.10k 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 saturated solution is at equilibrium: dissolving rate equals crystallization rate. Concentration of dissolved solute is constant (the solubility). Undissolved solid can be present. Unsaturated: more solute can still dissolve. Supersaturated: unstable excess (not the Chem 20 default case).

Worked example

At 20 °C a KCl solution with extra crystals on the bottom: saturated; ions still leave and rejoin the crystal at equal rates. Heating can unsaturate it as solubility rises.

Guided practice

1. Describe equal rates of dissolving and crystallization in a KCl slurry at 20 °C with extra crystals visible.
2. Near-miss: “saturated means no more dissolving ever occurs.” Mark the first wrong line.

Independent practice

1. What heating can do to a saturated KCl mixture (solubility rises - unsaturate).
2. Two sentences: dynamic equilibrium, not static stop.
3. Supersaturated as a later caution - do not claim this lesson produces one at home.

Diagram / whiteboard

Approved diagram id chem20-ph-scale - pH scale / solution concentration axes. 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

Defining saturated as “cannot dissolve because it is full of molecules that stopped moving.”

Safety and lab register

Setting: concentration and pH on paper or school-prepared dilute solutions. Red-cabbage indicator is classroom-supervised or photo/dataset. No concentrated acids or bases. No tasting. Dilution math is not a licence to mix cleaners. Forbidden: bleach+acid, drain opener, battery acid, undiluted pool chemicals. AI Tutor must not invent titrations or acid labs outside the register.

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

Formative evidence

One paragraph: saturated = equal rates, crystals persist.

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

AI Tutor / human tutor

Ground on 20-C1.10k. 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.