AP Intermolecular Forces and Properties 2

Question 1

Which of the following pairs of substances would be expected to be miscible (mix completely) in each other?

Accepted Answer

Ethanol (C₂H₅OH) and water (H₂O)

Answer

Hexane (C₆H₁₄) and water (H₂O)

Answer

Octane (C₈H₁₈) and water (H₂O)

Answer

Carbon tetrachloride (CCl₄) and water (H₂O)

Question 2

Arrange the following substances in order of increasing boiling point: CH₄, NH₃, Ne, HF.

Accepted Answer

Ne < CH₄ < NH₃ < HF

Answer

CH₄ < Ne < HF < NH₃

Answer

Ne < CH₄ < HF < NH₃

Answer

CH₄ < Ne < NH₃ < HF

Question 3

Why does ice float on liquid water, which is unusual for solids compared to their liquid phases?

Accepted Answer

Ice has a less dense crystal structure due to directional H-bonding that holds molecules in an open hexagonal lattice, making solid water less dense than liquid water

Answer

Ice has higher kinetic energy than liquid water, causing expansion

Answer

Water molecules are smaller in the solid phase due to compressed H-bonds

Answer

Ice floats due to surface tension, not density differences

Question 4

Which of the following has the highest viscosity at room temperature?

Accepted Answer

Glycerol (HOCH₂CHOHCH₂OH)

Answer

Ethanol (C₂H₅OH)

Answer

Water (H₂O)

Answer

Hexane (C₆H₁₄)

Question 5

What is the primary intermolecular force responsible for DNA's double helix structure holding together the two strands?

Accepted Answer

Hydrogen bonding between complementary base pairs (A-T and G-C)

Answer

Covalent bonding between bases on opposite strands

Answer

Ionic interactions between positively and negatively charged bases

Answer

London dispersion forces between stacked bases

Question 6

A substance has a high melting point, conducts electricity only when molten or dissolved in water, and is hard but brittle. What type of solid is it?

Accepted Answer

Ionic solid

Answer

Metallic solid

Answer

Covalent network solid

Answer

Molecular solid