Canonical lesson CHEMISTRY20-U3-L08 · outcome 20-C1.8k · depth CURRICULUM_BASELINE

Unit C: Solutions, Acids, Bases and Equilibrium intro - outcome 20-C1.8k

• Course: CHEMISTRY20 (SCN2796)
• Lesson ID: CHEMISTRY20-U3-L08
• Official outcome: 20-C1.8k (KNOWLEDGE)
• Object type: canonical lesson (not a bootcamp session)
• Source: Alberta Chemistry 20 Program of Studies (2007, updated 2014)

Official outcome text

use data and ionization/dissociation equations to calculate the concentration of ions in a solution

Learning intention

Meet 20-C1.8k 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

Write the dissociation: Na2SO4(s) → 2 Na+(aq) + SO42−(aq). Ion concentration = stoichiometric factor × formula-unit concentration. 0.10 mol/L Na2SO4 gives 0.20 mol/L Na+ and 0.10 mol/L SO42−. CaCl2: 1 : 2 for Ca2+ : Cl−.

Worked example

0.250 mol/L AlCl3 → [Al3+] = 0.250 mol/L, [Cl−] = 0.750 mol/L. Weak acids are not fully ionized - do not treat 0.10 mol/L CH3COOH as 0.10 mol/L H3O+ (that is Unit C2).

Guided practice

1. 0.100 mol/L Na2SO4: [Na+] and [SO42−]. Do not copy AlCl3.
2. Near-miss: 0.10 mol/L CH3COOH treated as [H3O+] = 0.10. Mark the first wrong line (weak acid; Unit C2).

Independent practice

1. 0.200 mol/L CaCl2 ion concentrations.
2. Write the dissociation equation used.
3. Charge-balance check of the ion concentrations.

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

Forgetting the subscript 2 in Na2SO4 when finding [Na+].

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

AlCl3 0.250 mol/L ion concentrations with the equation.

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

AI Tutor / human tutor

Ground on 20-C1.8k. 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.