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 changes the molecular structure of the substance. Examples include burning, rusting, and baking.

Front

What happens to the molecules during a physical change?

Back

During a physical change, the molecules of a substance rearrange but do not change their chemical structure. The substance remains the same at the molecular level.

Front

What happens to the molecules during a chemical change?

Back

During a chemical change, the molecules of a substance break apart and recombine to form new substances with different properties.

Front

Is melting ice a physical or chemical change?

Back

Melting ice is a physical change because the water molecules remain the same; only their state changes from solid to liquid.

Front

Is burning wood a physical or chemical change?

Back

Burning wood is a chemical change because it produces new substances, such as ash and gases, through a chemical reaction.

Front

What is an example of a chemical change in cooking?

Back

Baking cookies is an example of a chemical change because the heat causes the ingredients to react and form new substances.

Front

What is rusting?

Back

Rusting is a chemical change that occurs when iron reacts with oxygen and moisture in the air, forming iron oxide (rust).

Front

What is an example of a physical change in nature?

Back

An example of a physical change in nature is the melting of snow, where the solid snow turns into liquid water without changing its chemical composition.

Front

What is the difference between a physical change and a chemical change?

Back

The main difference is that a physical change does not alter the chemical composition of a substance, while a chemical change results in the formation of new substances.