Question

Considering the boiling points of the compounds below, predict their relative vapor pressures at 25 °C. Arrange the compounds according to their relative vapor pressures. (highest to lowest)

- Water bp 100°C
- diethyl ether bp 35°C
- Benzene bp 80°C
- Hexane bp 69°C

Answer 1

The relative vapor pressures of the compounds at 25 °C, from highest to lowest, are diethyl ether, hexane, benzene, and water. This is due to their respective boiling points, which indicate the strength of their intermolecular forces, with diethyl ether having the weakest and water the strongest.

Step-by-step explanation:

To predict the relative vapor pressures at 25 °C for the compounds water, diethyl ether, benzene, and hexane, we can look at their boiling points and infer about their intermolecular forces.

The compound with the lowest boiling point will have the highest vapor pressure because it requires less energy to convert into a gas, indicating weaker intermolecular forces.

Conversely, the compound with the highest boiling point will have the lowest vapor pressure, suggesting stronger intermolecular forces.

• Diethyl ether (bp 35 °C) has the weakest intermolecular forces and thus the highest vapor pressure.
• Hexane (bp 69 °C) has a higher boiling point than diethyl ether but lower than benzene and water, indicating the second highest vapor pressure.
• Benzene (bp 80 °C) has stronger intermolecular forces than hexane and diethyl ether, correlating to a lower vapor pressure.
• Water (bp 100 °C) with its strong hydrogen bonding has the lowest vapor pressure among the given compounds.

Therefore, the order from highest to lowest vapor pressures at 25 °C would be: diethyl ether > hexane > benzene > water.