Question

match the items in the left column to the appropriate blanks in the sentence on the right.

the substance ( ch_3ch_2oh ) will be a at room temperature because it has intermolecular force(s), while ( ch_3och_3 ) will be a at room temperature because it has intermolecular force(s)

Explanation:

• For \(CH_3CH_2OH\):
• \(CH_3CH_2OH\) (ethanol) has an \(-OH\) group. The oxygen - hydrogen bond in the \(-OH\) group is highly polar. Hydrogen bonding occurs when a hydrogen atom is bonded to a highly electronegative atom (in this case, \(O\)). In addition to hydrogen bonding, all molecules have dispersion forces (due to the motion of electrons creating temporary dipoles). Also, because of the polar \(O - H\) and \(C - O\) bonds, dipole - dipole forces are present. So, \(CH_3CH_2OH\) has hydrogen bonding, dipole - dipole, and dispersion intermolecular forces. These strong intermolecular forces hold the molecules together more tightly, so it is a liquid at room temperature.
• For \(CH_3OCH_3\):
• \(CH_3OCH_3\) (dimethyl ether) has a polar \(C - O\) bond. So, it has dipole - dipole forces. And like all molecules, it has dispersion forces. But it does not have hydrogen bonding (because the hydrogen atoms are not bonded to a highly electronegative atom like \(O\) in a way that can form hydrogen bonds as in \(CH_3CH_2OH\)). The intermolecular forces (dipole - dipole and dispersion) in \(CH_3OCH_3\) are weaker compared to those in \(CH_3CH_2OH\), so it is a gas at room temperature.

Answer:

The substance \(CH_3CH_2OH\) will be a liquid at room temperature because it has hydrogen bonding, dipole - dipole, and dispersion intermolecular force(s), while \(CH_3OCH_3\) will be a gas at room temperature because it has only dipole - dipole and dispersion intermolecular force(s).