AP Chemistry Unit 3 practice questions: Properties of Substances and Mixtures
8 original multiple-choice questions on AP Chem Unit 3, properties of substances and mixtures. Answer each one in your browser and read the explanation, then review the key ideas below.
Question 1 of 8
Which substance has the highest boiling point?
Question 2 of 8
A gas occupies 4.0 L at 2.0 atm. At constant temperature, the pressure is raised to 4.0 atm. What is the new volume?
Question 3 of 8
What is the molarity of a solution made by dissolving 0.50 mol of NaCl in enough water to make 250 mL of solution?
Question 4 of 8
Which intermolecular forces exist between CH₄ molecules?
Question 5 of 8
According to Beer's law, what happens to absorbance if the concentration of a solution doubles (same cuvette and wavelength)?
Question 6 of 8
What volume does 1.00 mol of an ideal gas occupy at 273 K and 1.00 atm?
Question 7 of 8
Air at 1.0 atm is 21% oxygen by moles. What is the partial pressure of oxygen?
Question 8 of 8
Which technique best separates two miscible liquids with different boiling points?
Key ideas in Unit 3
- Intermolecular forces (London dispersion, dipole-dipole, hydrogen bonding) explain boiling points, vapor pressure and solubility. Larger, more polarizable molecules have stronger dispersion forces.
- Ideal gases follow PV = nRT; Dalton's law adds partial pressures. Real gases deviate at high pressure and low temperature.
- Solutions: molarity = moles of solute ÷ liters of solution; like dissolves like.
- Separation methods (filtration, distillation, chromatography) rely on differences in physical properties.
- Spectroscopy: Beer's law A = εbc makes absorbance proportional to concentration.
More AP Chem practice
← Unit 2: Compound Structure and Properties
Unit 4: Chemical Reactions →
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