Bonding Practice Quiz #3

A certain crystalline substance that has a low melting point does not conduct electricity in solution or when melted. This substance is likely to be

• a covalent network solid

• a metallic solid

• a polymer

• an ionic solid

• a molecular solid

A sample of a hard, solid binary compound at room temperature did not conduct electricity as a pure solid but became highly conductive when dissolved in water. Which of the following types of interactions is most likely found between the particles in the substance?

• Ionic bonds

• Metallic bonds

• Covalent bonds

• Hydrogen bonds

A student is given a sample of a pure, white crystalline substance. Which of the following would be most useful in providing data to determine if the substance is an ionic compound?

• Examining the crystals of the substance under a microscope

• Determining the density of the substance

• Testing the electrical conductivity of the crystals

• Testing the electrical conductivity of an aqueous solution of the substance

At 298 K and 1 atm, Br₂ is a liquid with a high vapor pressure, and Cl₂ is a gas. Those observations provide evidence that under the given conditions, the

• forces among Br₂ molecules are stronger than those among Cl₂ molecules

• forces among Cl₂ molecules are stronger than the Cl−Cl bond

• Br−Br bond is stronger than the Cl−Cl bond

• Cl−Cl bond is stronger than the Br−Br bond

At room temperature I₂(s) is a molecular solid. Which of the following provides a characteristic of I₂(s) with a correct explanation?

• It has a high melting point because it has weak intermolecular forces.

• It is hard because it forms a threedimensional covalent network.

• It is not a good conductor of electricity because its valence electrons are localized in bonding and nonbonding pairs.

• It is very soluble in water because its molecules are polar.

Based on the data in the table above, which of the following liquid substances has the weakest intermolecular forces?

• C₆H₆(l)

• C₂H₅OH(l)

• CH₃OH(l)

• C₂H₆O₂(l)

Which statement best helps to explain the observation that NH₃(l) boils at -28^oC, whereas PH₃(l) boils at -126^oC?

• The dispersion forces in NH₃ are weaker than the dispersion forces in PH₃.

• The dispersion forces in NH₃ are stronger than the dipole-dipole forces in PH₃.

• NH₃ has hydrogen bonding that is stronger than the dipole-dipole forces in PH₃.

• NH₃ has hydrogen bonding that is weaker than the dipole-dipole forces in PH₃.

The electron cloud of HF is smaller than that of F₂, however, HF has a much higher boiling point than F₂ has. Which of the following explains how the dispersion-force model of intermolecular attraction does not account for the unusually high boiling point of HF?

• F₂ is soluble in water, whereas HF is insoluble in water.

• The F₂ molecule has a greater mass than the HF molecule has.

• Liquid F₂ has weak dispersion force attractions between its molecules, whereas liquid HF has strong ionic interactions between H⁺ and F^- ions.

• Liquid F₂ has weak dispersion force attractions between its molecules, whereas liquid HF has both weak dispersion force attractions and hydrogen bonding interactions between its

  molecules.

In solid methane, the forces between neighboring CH₄ molecules are best characterized as

• ionic bonds

• covalent bonds

• hydrogen bonds

• ion-dipole forces

• London (dispersion) forces

In the diagram above, which of the labeled arrows identifies hydrogen bonding in water?

• A

• B

• C

• D