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 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

Why ionic solids are brittle

Network covalent solids

Molecular geometries

Expanded octet

Bond polarity vs molecular polarity

VSEPR theory

Bond energy and length

Conductivity of ionic compounds

Lattice energy

Coulombic reasoning for melting point

Alloys

Hybridization

Short answer 1. Define or explain: Resonance

3 pts

Short answer 2. Define or explain: Covalent bonding

3 pts

Short answer 3. Define or explain: Formal charge

3 pts

Short answer 4. Define or explain: Metallic bonding

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 student measures initial-rate data at constant temperature for the decomposition 2 N₂O₅(g) → 4 NO₂(g) + O₂(g). Trial 1: [N₂O₅] = 0.010 M, rate = 4.8 × 10⁻⁶ M/s Trial 2: [N₂O₅] = 0.020 M, rate = 9.6 × 10⁻⁶ M/s The reaction has an activation energy of 103 kJ/mol.

Determine the order of the reaction with respect to N₂O₅, and write the rate law.

Calculate the rate constant k, including units.

Describe the reaction-energy diagram for this reaction, identifying what must be labeled on it.

Explain the effect of adding a catalyst on the activation energy and on the rate.