Use these targets, vocabulary, rubrics, examples, and score sheet with the instructor's approved lesson and procedure. This is an assessment companion, not a complete lesson or safety authorization.
Student lessons, data, and worked answers: Unit 07 learning pathway.
The student demonstrates the following:
Five science criteria plus separately reported integration (Page 3).
Use a justified endpoint near equivalence; calculate with the balanced mole ratio.
The student explains pH on a log scale (Page 4).
Burette readings, calculation, and result kept distinct.
You are making a decision, not adding up points. For each criterion, decide whether the work is Developing, Proficient, or Mastery — the column language tells you which. Judge each science criterion from its own independent evidence; titration success alone does not establish every criterion. Each student has three tokens per term; each token retries one rubric criterion. Approved accommodations, equipment failures, and approved absences are handled separately and do not consume these tokens.
Accept listed synonyms; use the distinction column to resolve near-matches.
| Canonical answer | Accepted synonyms | Common confusion / discriminator |
|---|---|---|
| Defining acids & bases | ||
| Brønsted–Lowry acid | proton donor | Donates H⁺; base accepts it — broader than Arrhenius |
| pH | −log[H⁺] | A log scale — one unit is a 10× change in [H⁺] |
| Strong vs weak acid | full vs partial dissociation | Strength ≠ concentration; a weak acid can still be concentrated |
| Neutralization | acid + base → salt + water | Produces water and a salt; not always pH 7 at equivalence |
| Solutions & titration | ||
| Molarity (M) | moles per liter | Concentration; use M₁V₁ = M₂V₂ for dilution |
| Equivalence point | stoichiometric point | Balanced stoichiometric ratio; equal moles only for a 1:1 reaction. The indicator endpoint approximates equivalence. |
| Buffer | weak acid/conjugate pair | Resists pH change; not the same as “neutral” |
| Indicator | pH dye (e.g. phenolphthalein) | Signals the endpoint by color change; choose to match the equivalence pH |
Choose an indicator whose transition matches the expected equivalence region. Approach the approved endpoint without a deliberate extra drop; report initial and final burette readings and endpoint uncertainty. Do not assume equal acid and base moles unless the balanced ratio is 1:1.
| Criterion | Developing | Proficient | Mastery |
|---|---|---|---|
| Acid–base definitions & pH | Confuses acids with bases or the pH direction. | Defines pH but cannot calculate it from concentration. | Applies acid/base definitions and proton-transfer classification; distinguishes strength from concentration, computes pH, and checks stoichiometric excess, equilibrium and water assumptions. |
| Concentration & solution prep | Cannot express or calculate molarity. | Calculates molarity but errs in dilution or prep. | Prepares and dilutes solutions to a target molarity and reports concentration correctly. |
| Titration & the equivalence point | Adds titrant past the endpoint with no notice. | Reaches an endpoint but cannot find the unknown concentration. | Identifies the equivalence point, explains why the endpoint only approximates equivalence, and computes unknown concentration using balanced stoichiometry. |
| Buffers & solubility | Treats every solution as freely changing pH. | Names buffers or solubility rules but applies them loosely. | Explains buffer action, checks neutralization and capacity, and uses solubility equilibria to compare solubility and predict precipitation under stated common-ion and pH conditions. |
| Lab technique (titration) | Misreads the burette or overshoots the endpoint. | Titrates but with inconsistent technique or drop control. | Performs a clean, reproducible titration with controlled drops and a justified endpoint. |
| Integration (cross-domain) | Makes no supported connection between the source and the science. | Uses the source but needs help connecting evidence, writing, or limitations to the science. | Independently connects History, Reading, and Writing using a cited source, appropriate evidence, a limitation, and a scientific explanation. |
Read these before you grade. They show what Mastery and Developing actually sound like, plus the edge cases where you should coach rather than decide on the spot.
Evidence record for Page 5: Level: ______ Case/dataset: ______ Criterion: ______ Work/source/date: ______ Assumptions/units/uncertainty: ______ Transfer/variant: ______ (Attach independent calculations; practical observation is separate.)
Student: ______________________________________ Date: _______________ Guide: _________________________
| # | Criterion | Decision | Notes |
|---|---|---|---|
| 1 | Acid–base definitions & pH | Dev / Prof / Mast | |
| 2 | Concentration & solution prep | Dev / Prof / Mast | |
| 3 | Titration & the equivalence point | Dev / Prof / Mast | |
| 4 | Buffers & solubility | Dev / Prof / Mast | |
| 5 | Lab technique (titration) | Dev / Prof / Mast | |
| 6 | Integration (cross-domain) | Dev / Prof / Mast |
☐ No ☐ Yes — for criterion: __________
Tokens left this term after this session (choose one): ☐ 3 ☐ 2 ☐ 1 ☐ None left
Dev = Developing · Prof = Proficient · Mast = Mastery · Unsure between two levels? Circle the lower one and note what a re-do would need.