CHEM20 Session 10 — Synthesis, misconception clinic, Milestone 1, exit assessment

Delivery id: CHEM20 (SCN2796)

Time: 75 minutes

Unit A (weeks 1–2 close): Diversity of Matter and Chemical Bonding

Alberta POS: https://open.alberta.ca/publications/3950147-updated-2014

Mastery: This hour starts evidence for Unit A GO1/GO2; it does not finish the unit (VSEPR practice and IMF still recycle later).

Official outcomes

Synthesis and check of: 20-A1.1k, 20-A1.2k, 20-A1.3k–20-A1.6k, 20-A2.1k–20-A2.10k, 20-A1.1s/20-A1.2s (evidence from Session 04), 20-A2.1sts.

Learning targets

1. Correct the week’s high-frequency errors in a clinic (no praise of the error).
2. Submit Project Milestone 1: Material Selection Brief (one page) using real formulas and bonding classes.
3. Complete an exit assessment covering naming, Lewis/VSEPR, IMF, polarity, and Session 04 interpretation.
4. State what is not yet Unit A complete (more practice, not new banned labs).

Prerequisites

Sessions 01–09. Session 04 data sheet in the folder. Draft material list from Session 09 homework.

Diagnostic/retrieval

Rapid oral (4 min) — teacher records class error tally, not individual shame:

1. Name Fe2O3.
2. Formula for dinitrogen pentoxide.
3. Shape of H2O and CO2.
4. Solid NaCl conductivity?
5. H-bonding in CH4?

Instruction

Clinic protocol: display a wrong statement; students write the repair; teacher reveals the correct model; do not say “good thinking” to the wrong statement.

Clinic items (fixed list):

1. “NaCl2 because chlorine is Cl2.” → NaCl; chloride is Cl−.
2. “(II) means two atoms of metal.” → cation charge.
3. “Solid salt conducts.” → ions not mobile.
4. “Sugar conducts because it dissolves.” → nonelectrolyte.
5. “Vinegar is ionic.” → molecular weak acid.
6. “N2O4 simplifies to NO2.” → molecular formula not reduced.
7. “CO2 is bent.” → AX2 linear.
8. “Boiling water makes H2 and O2.” → IMF, still H2O(g).
9. “CH4 hydrogen-bonds.” → H on C, no.
10. “ΔEN ≥ 1.7 proves HF is an ionic lattice.” → continuum; HF molecular.
11. “Bleach + vinegar is a polar-cleaner hack.” → Cl2(g); banned.

Then 8 minutes: Milestone 1 requirements on the board (see Project connection). Then 28 minutes: exit assessment (individual, silent). Remaining time: folder check / return Session 04.

Timed visuals

id	trigger	duration	alt	teacher cue	tutor cue
CHEM20-VIS-10-CLINIC	After retrieval	90 s	Eleven crossed-out sentences	“Write the repair. Do not defend the error.”	No false praise.
CHEM20-VIS-10-BRIEF	Minute 22	40 s	Brief boxes: formula / class / solubility / conductivity / safety tag	“Three materials. Real formulas.”	Refuse bleach rows.
CHEM20-VIS-10-QUIET	Assessment start	15 s	Silent / no tutor during test	Devices away	Tutor off during the assessment.

Modelling/worked examples

Milestone 1 exemplar (teacher-written, students may not copy wholesale):

Material	Formula	Bonding class	Predicted solubility in H2O	Predicted conductivity(aq)	IMF or lattice	Safety tag
Table salt	NaCl	ionic lattice	high	high (Na+, Cl−)	ionic intramolecular	home-safe as food; lab: no tasting
Water	H2O	polar covalent molecule, bent	n/a (solvent)	none if distilled	H-bonding	home-safe
Vinegar (acetic acid soln.)	CH3COOH(aq)	polar molecular (weak electrolyte)	miscible	low	H-bonding	classroom goggles; never + bleach; consumer home-safe for cooking, not for mixing

Worked assessment item: Name CuSO4·5H2O; Lewis/shape/polarity of NH3; rank BP F2 < Cl2 < Br2; interpret a data row “sucrose LED = none.”

Guided practice + answers

Clinic repairs are the guided practice. Answers: see list in Instruction and teacher-solutions.md Session 10.

Brief peer-check (2 min): partner looks only for banned chemicals and missing formulas, not for “niceness.”

Independent practice

The exit assessment is the independent work. Differentiation:

• FOUNDATION: Items 1–6 (naming ions/molecules, one Lewis H2O, conductivity of NaCl(aq) vs solid, one polarity).
• CORE: Full paper items 1–12.
• PROFICIENT: Full paper + item 13 (HF continuum) + item 14 (Session 04 error analysis).
• ADVANCED: Full paper + item 15 (C2H5OH vs CH3OCH3 BP) + one additional sentence on the brief connecting like-dissolves-like to the chosen nonpolar material.

Students who finish early improve the brief; they do not start a new lab.

Project connection

Milestone 1 — Material Selection Brief (submit today).

Required:

• Title: Safe water / cleaning chemistry — Milestone 1
• Three candidate materials with real formulas
• Bonding class (ionic lattice / polar molecular / nonpolar molecular)
• Predicted solubility in water and conductivity(aq) with a one-line model
• Safety tag: classroom-supervised / teacher demo / home-safe / forbidden
• Explicit sentence: bleach+acid and bleach+ammonia will not be used
• Session 04 evidence cited if salt/sugar/vinegar appear

Not required: cost spreadsheet, logo, bacterial claims, medical disinfectant claims.

Checks

Before assessment: “Tutor off?” Devices in bag. During brief: teacher scans for NaClO / NH3 as selected process chemicals → return for revision, not a bonus.

Misconceptions

Reuse the clinic table. Additional:

Wrong	Repair	Do not say
“Milestone 1 is a lab report of a home experiment.”	It is a selection brief from class evidence.	—
“I finished Unit A.”	Weeks 1–2 launched GO1/GO2; more Unit A remains.	“You’re done bonding forever.”
“The AI can grade my test.”	Human teacher. Tutor off.	—

AI Tutor prompts and boundaries

Before assessment: allowed clinic prompts from Sessions 01–09 lists.

During assessment: tutor disabled.

After: may review missed items; must not invent makeup labs; must not say “great job” on a wrong FeCl3 name.

Human-tutor handoff

Reader/scribe as IEP allows on the assessment. Brief may be scribed. If a student missed Session 04, they use the class sample data table (labelled as class data, not their own) and still write the model.

Exit ticket + answers

The assessment is the exit ticket. CORE key (short):

1. Fe2O3 iron(III) oxide.
2. Ca3(PO4)2.
3. N2O5 dinitrogen pentoxide.
4. NaCl not Na2Cl2 because simplest 1:1 ratio, net charge zero.
5. Lewis H2O: 8 e, two bonds, two lone pairs; shape bent.
6. CO2 linear, nonpolar molecule.
7. NH3 trigonal pyramidal, polar.
8. Solid NaCl: no conduction; NaCl(aq): yes.
9. Sucrose(aq): no conduction (molecules).
10. Dominant IMF in I2: London; in H2O: H-bonding.
11. CH4 does not H-bond.
12. Bleach + vinegar: forbidden, Cl2(g).

PROFICIENT 13: HF polar covalent molecule, not a NaCl-type lattice.

PROFICIENT 14: bright LED in sugar cup → contamination, not “sugar is ionic.”

ADVANCED 15: ethanol H-bonds, dimethyl ether does not; ethanol higher BP (78 °C vs −25 °C).

Full numbered paper lives in teacher-solutions.md.

Homework

None required. Optional: correct the assessment in green pen after it is returned (Session 11+). Do not perform kitchen experiments.

Teacher guidance

Grade the brief with a 6-point rubric: formulas, bonding class, solubility, conductivity model, safety tag, ban sentence. Assessment: CORE /12. Do not share the key on the projector while stragglers write. Log 20-A1.1k etc. as introduced/evidenced, not unit-complete.

Materials

Clinic slides; brief template; assessment papers FOUNDATION/CORE/PROFICIENT/ADVANCED; Session 04 data extras; device caddy.

Preparation

Print four assessment versions or one paper with labelled extension items. Seat plan for silent work. Rubric on the back of the brief.

Timing

Min	Move
0–4	Retrieval tally
4–20	Misconception clinic
20–30	Milestone 1 finalize / submit
30–62	Exit assessment
62–75	Collect, folder check, “Unit A continues”

If Milestone 1 is incomplete, accept by end of day on paper; do not send a home lab to “finish with better data.”

Online alternative

LMS quiz lock-down (no tutor). Brief as file upload. Same bans. Camera-on optional per school policy.

Low-technology alternative

All paper. Clinic on the board. Brief handwritten. Assessment handwritten.