Chemistry · Unit 8 · Paper 2

Acids & Bases unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1 Paper 2 Paper 3

Each paper is built from this unit’s 20 terms and is the same for everyone, so a teacher can assign “Unit 8, Paper 2” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.

Suggested time 37 min 34 points0/17 attempted

Ka and acid strength

Choosing an indicator

Buffer

Diluting a buffer

Relationship of Ka and Kb

Amphoteric species

Equivalence point pH

Brønsted-Lowry definition

Strong vs weak acids

Structure and acid strength

Polyprotic acids

Henderson-Hasselbalch equation

Short answer 1. Define or explain: Autoionization of water

3 pts

Short answer 2. Define or explain: Buffer capacity

3 pts

Short answer 3. Define or explain: Percent ionization

3 pts

Short answer 4. Define or explain: Titration curve of a weak acid

3 pts

Free response

10 pts

A 0.500 L buffer solution contains 0.20 M acetic acid (CH₃COOH, Ka = 1.8 × 10⁻⁵) and 0.20 M sodium acetate (CH₃COONa).

Calculate the pH of the buffer.

Calculate the pH after 0.010 mol of solid NaOH is added. Assume no change in volume.

Explain why this solution resists changes in pH.

Identify which component of the buffer reacts with added HCl.