JDES Physical and Chemical Changes

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Examples include melting, freezing, and dissolving.

A chemical change is a change that results in the formation of new chemical substances. It involves a chemical reaction and includes processes like burning, rusting, and digestion.

Soot is a black powdery substance that is produced when wood or other organic materials burn. It is a result of incomplete combustion.

When water boils, it changes from a liquid to a gas (steam) due to the increase in temperature.

Rust is a reddish-brown flaky substance that forms when iron reacts with oxygen and moisture in the air, resulting in a chemical change.

An example of a physical change is ice melting into water.

An example of a chemical change is wood burning to produce ash and smoke.

Evaporation is the process by which liquid water turns into water vapor (gas) when it is heated.

Condensation is the process by which water vapor (gas) cools and turns back into liquid water.

A physical change does not alter the chemical composition of a substance, while a chemical change results in the formation of new substances.