Physical and Chemical Changes

Front

What is a physical change?

Back

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.

Front

What is a chemical change?

Back

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.

Front

What is an indication of a chemical change?

Back

Indications of a chemical change include color change, temperature change, gas production, and the formation of a precipitate.

Front

Is burning wood a chemical or physical change?

Back

Burning wood is a chemical change because it transforms the wood into new substances such as ash, smoke, and gases.

Front

Is rusting a chemical or physical change?

Back

Rusting is a chemical change because it involves the reaction of iron with oxygen to form iron oxide (rust).

Front

What happens to thermal energy during a chemical reaction?

Back

Thermal energy (heat) is either released or absorbed during a chemical reaction, which can lead to a change in temperature.

Front

What is an example of a physical change?

Back

An example of a physical change is when ice melts into water. The chemical composition of water remains the same.

Front

What is an example of a chemical change?

Back

An example of a chemical change is the burning of paper, which produces ash and smoke.

Front

What does it mean when a substance dissolves in water?

Back

When a substance dissolves in water, it undergoes a physical change, resulting in a homogeneous mixture without changing its chemical identity.

Front

What is a precipitate?

Back

A precipitate is a solid that forms and settles out of a liquid mixture during a chemical reaction.