Which evaporates more quickly: 55 ml of water (h2o) in a beaker or 55 ml of acetone [(ch3)2co] in an identical beaker under identical conditions? is the vapor pressure of the two substances different? explain?

Between 55 ml of water (h2o) in a beaker or 55 ml of acetone [(ch3)2co] in an identical beaker under identical conditions, acetone will evaporate more quickly as in water intermolecular hydrogen bonding will takes place due to presence of highly polar O-H bond in H2O molecule. This bonding is not possible in acetone . That makes acetone more volatile than water and evaporates faster.

Acetone will evaporate quickly.

Vapor pressure of acetone will be more.

Explanation:

The water molecule has a hydrogen bonded to highly electronegative element , oxygen. Due to this the water molecule is able to form hydrogen bond with another water molecule (inter-molecular). Due to inter molecular hydrogen bonds the water molecules need high temperature to convert to vapors.

While in case of acetone intermolecular hydrogen bond between acetone molecules is not possible as there is no hydrogen attached to an electronegative element like F,O or N. Thus acetone will get converted to vapors easily.

The vapor pressure of acetone will be high as compared to water at the same temperature.