Conservation of Mass and Volume Changes During State Changes
This page covers two key concepts related to state changes of matter:
- Conservation of mass during state changes
- 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.