Physical and Chemical Changes/Law of Conservation of Mass

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

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.

Front

Classify the following as a physical or chemical change: Food is digested in the stomach.

Back

Chemical

Front

Classify the following as a physical or chemical change: Milk sours.

Back

Chemical

Front

Classify the following as a physical or chemical change: Grass growing in a lawn.

Back

Chemical

Front

Classify the following as a physical or chemical change: Water is absorbed by a paper towel.

Back

Physical

Front

Classify the following as a physical or chemical change: Sodium hydroxide dissolves in water.

Back

Physical

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 their chemical structure remains the same.