Chapter U3.8, Problem 5E

Interpretation Introduction

Interpretation:Comprehend the evidence for the movement of water molecules apar very slightly during freezing of water.

Concept Introduction: Matter can exist in three possible states of matter; solid, liquid and gases.

Solids are the substances with least intermolecular distance and strongest intermolecular forces whereas gases have largest intermolecular distance and weakest intermolecular forces.

Liquids have intermediate value of intermolecular distance and intermolecular forces.

These states of matter can interconvert into each other and is called as interconversion of states of matter.

Answer to Problem 5E

Ice is less dense than water due to movement of water molecules slightly apart compare to liquid water.

Explanation of Solution

Freezing is the interconversion of liquid state to solid state. When water freezes, the water molecules come close to each other therefore the volume decreases. But after a certain temperature (4°C), it shows expansion.

This is because water molecules are bonded with each other through hydrogen bonds in a line. During freezing of water molecules, water molecules come close to each other but close to freezing point, water molecules arranged in a cage like structure with the help of formation of hydrogen bonds with each other therefore it shows expansion of molecules. It can be proved by density of ice and water. Ice is less dense than water due to movement of water molecules slightly apart compared to liquid water.