Intermolecular Forces 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 22 terms and is the same for everyone, so a teacher can assign “Unit 3, Paper 3” 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

Distillation

Dipole-dipole forces

Maxwell-Boltzmann distribution

Ideal gas law

Hydrogen bonding

Effusion and Graham's law

Molarity

Kinetic molecular theory assumptions

Vapor pressure

Surface tension and viscosity

Solubility and "like dissolves like"

Real gas deviation direction

Short answer 1. Define or explain: Why intermolecular forces are weaker than bonds

3 pts

Short answer 2. Define or explain: Capillary action

3 pts

Short answer 3. Define or explain: Ion-dipole forces

3 pts

Short answer 4. Define or explain: Chromatography

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 0.750 g sample of impure calcium carbonate is treated with excess hydrochloric acid: CaCO₃(s) + 2 HCl(aq) → CaCl₂(aq) + H₂O(l) + CO₂(g). The CO₂ produced is collected over water at 25 °C, where the total pressure is 755 torr and the collected volume is 155 mL. The vapor pressure of water at 25 °C is 23.8 torr.

Calculate the partial pressure of CO₂ in atmospheres.

Calculate the number of moles of CO₂ collected.

Calculate the mass percent of CaCO₃ in the original sample.

Explain the direction in which the calculated mass percent would be biased if the student forgot to subtract the water vapor pressure.

Describe one experimental observation that would confirm the HCl was truly present in excess.