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 chemical composition of the substance. Examples include rusting, burning, and digestion.

Front

Give an example of a physical change.

Back

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

Front

Give an example of a chemical change.

Back

An example of a chemical change is the burning of wood.

Front

What are some indicators of a chemical change?

Back

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

Front

What happens to the molecules during a physical change?

Back

During a physical change, the arrangement of molecules may change, but the molecules themselves remain the same.

Front

What happens to the molecules during a chemical change?

Back

During a chemical change, the bonds between molecules are broken and new bonds are formed, resulting in new substances.

Front

Is dissolving sugar in water a physical or chemical change?

Back

Dissolving sugar in water is a physical change because the sugar can be recovered by evaporating the water.

Front

Is burning paper a physical or chemical change?

Back

Burning paper is a chemical change because it produces ash and smoke, which are different substances.

Front

What is the law of conservation of mass?

Back

The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; the total mass of the reactants equals the total mass of the products.