Unit 07 · Acids, Bases & Solutions
This unit lives at the burette. It covers what acids and bases are, the meaning and math of pH, how to prepare and report concentration, how a titration finds an unknown concentration, how buffers resist pH change, and how solubility governs what dissolves and what precipitates. Mastery means you can take a solution of unknown strength and determine it — cleanly, with a justified endpoint and correct math.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Acid–base definitions & pH | Confuses acids with bases or the pH direction. | Defines pH but cannot calculate it from concentration. | Relates strength, [H⁺], and pH, and distinguishes strong from weak acids and bases. |
| 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 and computes the unknown concentration from titration data. |
| Buffers & solubility | Treats every solution as freely changing pH. | Names buffers or solubility rules but applies them loosely. | Explains how a buffer resists pH change and predicts precipitation from solubility rules. |
| 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) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“I titrated to the first lasting pink, read the burette at eye level, and used C₁V₁ over the balanced ratio to find the unknown molarity — to three significant figures, because that’s all my volumes support.”
“I added base until it turned pink and overshot a bit. pH is how acidic it is. I’m not sure how to get the concentration from the numbers.”
You demonstrate this unit by titrating an unknown to its equivalence point, defending your endpoint choice and concentration calculation aloud — not a multiple-choice test. A criterion counts as mastered only when your technique is reproducible and your math is justified at the bench. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.