Based on the molecular diagram, classify each change as physical or chemical.

Key Concepts

Physical Change

A physical change involves a change in the state or appearance of a substance without altering its chemical composition. Examples include changes in state (solid to liquid), shape, or size. In the provided molecular diagram, the blue molecules spreading apart represent a physical change, as their identity remains unchanged despite the increase in distance between them.

Chemical Change

A chemical change results in the formation of one or more new substances with different chemical properties. This process often involves the breaking and forming of chemical bonds. The second molecular diagram illustrates a chemical change, where blue and green molecules rearrange, indicating that new substances are formed through the interaction of different types of molecules.

Molecular Representation

Molecular representation visually depicts the arrangement and interaction of molecules during physical and chemical changes. Understanding these diagrams helps in identifying the nature of the change occurring. The diagrams in the question serve as a tool to differentiate between physical changes, where molecules merely spread apart, and chemical changes, where molecular rearrangement occurs, leading to new substances.