AP Chemistry: Intermolecular Forces and Properties Practice Test

What explains the very high melting and boiling point of water?

Hydrogen bonding occurs when hydrogen is bonded to N, O, or F. Which of the following has hydrogen bonding?

All molecules have London forces between them, but dipole-dipole and hydrogen bonding are so much stronger that when they are present we can ignore London forces. Which of these has ONLY London forces?

Which substance would have the weakest intermolecular forces of attraction?

Determine the type of intermolecular force present in SiO₂ .

What is the basis of a metallic bond?

Which of the following would best remove Sharpie marker from your wall if this marker is known to be non-water soluble?

Which of the following has the lowest boiling point?

What will be the state of the following molecule?

Which of the following cations is likely to have the strongest attraction to an adjacent water molecule in an aqueous solution?

The Lewis structure of benzene is shown below.

Which of the following identifies all of the intermolecular forces present among molecules of benzene?

Which of the following correctly lists the HCN, N 2 , and HF in order of increasing intermolecular forces?

In the vapor phase, formic acid exists as dimers (complexes consisting of two formic acid molecules) rather than individual molecules. The formic acid dimer is held together by two hydrogen bonds.

Which of the following diagrams correctly represents the hydrogen bonding (denoted by dotted lines) in the formic acid dimer?

The diagram below represents five molecules of Br₂ in the liquid state.

Which of the following diagrams best represents the molecules of Br₂ after complete vaporization has occurred?

Obsidian, a type of volcanic glass, consists mainly of silicon dioxide (SiO₂ ). The general structure of obsidian is shown below.

Based on the diagram above, which of the following can be concluded about obsidian?

Samples of four pure dyes, labeled A through D, are spotted on chromatography paper (a polar material) at the positions indicated in the diagram below. An unknown dye sample, labeled X, is then spotted on a separate piece of chromatography paper. Both papers are placed in chromatography chambers containing a small amount of a nonpolar solvent and developed. The developed chromatograms are shown below on
the right.

Which of the four dyes is most likely present in sample X?

A student performs a distillation of a 2 : 1 mixture of two straight-chain hydrocarbons, hexane (C₆ H₁₄ ) and heptane (C₇ H₁₆ ). During the distillation, the student collects fractions of distillate over three volume ranges. These fractions, labeled A, B, and C, are indicated on the distillation curve below.

Based on the curve, what is the most likely composition of fraction C?

The results of a thin-layer chromatography (TLC) experiment are shown above. In the experiment, a TLC plate coated with a thin layer of silica gel (a polar material) was spotted with a mixture containing two different polar pigments. The plate was then developed using a solvent mixture of 70%, percent pentane and 30%, percent diethylether. The relative polarities of pentane, diethyl ether, and another common TLC solvent, ethyl acetate, are shown in the table below.

According to the information above, which of the following changes to the solvent mixture would likely decrease the R f values of the pigments in a subsequent experiment?