Conservation of Mass and Volume Changes During State Changes

This page covers two key concepts related to state changes of matter:

1. Conservation of mass during state changes
2. Volume variation during state changes

Conservation of Mass

The mass remains constant during a state change of a pure substance. This is because the number of molecules stays the same, they just rearrange.

Example: When ice cubes melt into liquid water, all the water molecules from the ice end up in the liquid - there is no loss of mass. This is why it's called a state change rather than a chemical reaction.

Highlight: A state change involves the same molecules rearranging, not transforming into different molecules.

Volume Variation

The volume of a substance changes during state changes due to the breaking or forming of bonds between molecules.

Example: When a full plastic water bottle is placed in a freezer, it deforms as the water expands when freezing into ice.

Vocabulary: Solidification - The process of a liquid changing to a solid state.

The page includes helpful diagrams showing mass conservation during ice melting and volume expansion during water freezing.