Canonical lesson CHEMISTRY20-U2-L02 · outcome 20-B1.2k · depth CURRICULUM_BASELINE

Unit B: Gases - outcome 20-B1.2k

• Course: CHEMISTRY20 (SCN2796)
• Lesson ID: CHEMISTRY20-U2-L02
• Official outcome: 20-B1.2k (KNOWLEDGE)
• Object type: canonical lesson (not a bootcamp session)
• Source: Alberta Chemistry 20 Program of Studies (2007, updated 2014)

Official outcome text

convert between the Celsius and Kelvin temperature scales

Learning intention

Meet 20-B1.2k 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

Kelvin is an absolute scale: T(K) = t(°C) + 273.15 (Chem 20 often uses +273). Absolute zero is 0 K = −273.15 °C. Gas laws must use kelvin because volume and kinetic energy scale with absolute temperature, not Celsius. 0 °C is not zero motion.

Worked example

25 °C → 298 K. −20 °C → 253 K. 310 K → 37 °C. Charles’s law with 25 °C and 50 °C as if 50/25 = 2 would be wrong; 323/298 ≈ 1.08.

Guided practice

1. Convert −40 °C to K and 400 K to °C. Show why a Charles’s-law doubling cannot use 10 °C → 20 °C as 20/10.
2. Near-miss: T2/T1 = 50/25 using Celsius. Mark the first wrong line.

Independent practice

1. 37 °C (body temperature) in kelvin.
2. Two sentences: why gas laws need an absolute scale.
3. Absolute zero in °C and K.

Diagram / whiteboard

Approved diagram id chem20-pv-boyle - P-V Boyle sketch (or gas law 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

Doubling Celsius and claiming volume doubles, or using negative kelvin.

Safety and lab register

Setting: datasets, simulations, and teacher demo of sealed apparatus only. Students do not generate gases, open compressed cylinders, or heat with flame. Boyle/Charles work uses a provided P-V or V-T table or PhET-class simulation. Forbidden: generating chlorine, hydrogen, or ammonia gas; dry ice in a sealed bottle as a student task; any kitchen-stove Charles’s-law balloon. AI Tutor must not invent gas-generation procedures.

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

Formative evidence

25 °C → 298 K and the false doubling trap in one line each.

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

AI Tutor / human tutor

Ground on 20-B1.2k. 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.