Molecular and Ionic Compound Structure and Properties 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 2, Paper 1” 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

Conductivity of ionic compounds

Network covalent solids

Hybridization

Lewis structures

Molecular geometries

Bond polarity vs molecular polarity

Metallic bonding

Alloys

Sigma vs pi bonds

VSEPR theory

Bond dipole

Covalent bonding

Short answer 1. Define or explain: Formal charge

3 pts

Short answer 2. Define or explain: Expanded octet

3 pts

Short answer 3. Define or explain: Why ionic solids are brittle

3 pts

Short answer 4. Define or explain: Coulombic reasoning for melting point

3 pts

Free response

10 pts

This course has no free-response prompt tagged to this unit, so one from elsewhere in the course is used. It is still worth writing — the skill transfers.

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.