Final answer:
Instant snow expands in water due to the polymer's affinity for the polar water molecules, facilitated by hydrogen bonding and ion-dipole interactions. This occurs because the water molecules are drawn to the charged groups within the polymer structure, causing it to swell.
Step-by-step explanation:
The interaction of instant snow and water can be understood in terms of polarity and intermolecular forces (IMFs). Instant snow is comprised of a polymer that can absorb water, swelling to many times its original size due to its affinity for water molecules. This affinity is largely due to hydrogen bonding, an intermolecular force that occurs between the polar water molecules and the charged groups on the polymer.
Water molecules are polar because of the difference in electronegativity between the hydrogen and oxygen atoms, creating positive and negative ends. When instant snow comes in contact with water, water's polarity and the hydrogen bonds it can form cause it to be drawn into the spaces within the polymer structure. This attraction is facilitated by ion-dipole interactions and hydrogen bonding, which are possible due to the polar nature of the water molecule.
The process of instant snow expanding upon contact with water is analogous to how water dissolves polar and ionic substances. The polymer in instant snow effectively 'dissolves' in water, not by breaking down chemically, but by rapidly taking in water through the action of its polar functional groups and expanding as the water molecules arrange around them in a structured manner.