Ch 7 Review

The molecules in a gas phase will

• speed up upon heating the gas.

• slow down upon heating the gas.

• change phase upon sufficient heating of the gas.

• form a condensed phase upon sufficient heating.

Condensation occurs when

• the temperature of a substance is adjusted to its melting point.

• the kinetic energy of the molecules is not sufficient to overcome intermolecular attractions.

• the molecules are moving in random directions.

• the kinetic energy of the molecules is sufficient to overcome intermolecular attractions.

A difference between the solid phase and the other two phases of a pure substance is

• only the solid phase has molecules in fixed positions.

• only the solid phase can experience melting.

• only the solid phase is at or below the freezing point of the substance.

• all of the above are correct.

Which of the following statements is true regarding London forces?

• They are present only in the gas phase.

• They are present only in the liquid phase.

• They are present only in the solid phase.

• They are present in all phases of matter.

Which of the following statements is true regarding London forces?

• They have nothing to do with the electrons in a molecule.

• They get smaller as the number of electrons in a molecule increases.

• They get larger as the number of electrons in a molecule increases.

• They get larger as the electrons get closer to the nucleus.

Which of the following statements is true regarding London forces?

• They are due primarily to valence electrons.

• They can never be stronger than dipolar attractions.

• They can be quite strong for molecules that possess many electrons.

• All of the above.

Hydrogen bonding is

• the name given to the chemical bond in the H-H or H2 molecule.

• a particularly strong type of dipolar interaction.

• as strong as a chemical bond.

• when hydrogen bonds to any other element.

A hydrogen bond between molecules can occur

• only if the molecules involved are nonpolar.

• only if the molecules possess a hydrogen atom bound to O, N, or F.

• only if full charges develop on the atoms instead of partial charges.

• only in the absence of dispersion forces.

A network solid is

• the easiest of solids to melt.

• made up of ions bound to one another via ionic bonds.

• made up of molecules attracted to one another.

• made up of atoms covalently bound to one another.

A condensed phase is

• a shortened (condensed) version of a substance.

• the gas form of a substance.

• the liquid and solid forms of a substance.

• formed by evaporation.