7th Grade Science Review

Front

What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means. Examples include Oxygen, Hydrogen, Carbon, and Nitrogen.

Front

Give an example of an element.

Back

Oxygen

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.

Front

Give an example of a physical change.

Back

Melting ice

Front

What is a compound?

Back

A compound is a substance formed by the chemical combination of two or more elements in definite proportions.

Front

Give an example of a compound.

Back

Water (H2O)

Front

What is a chemical change?

Back

A chemical change is a change that results in the formation of new chemical substances.

Front

Give an example of a chemical change.

Back

Burning of wood

Front

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

Back

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

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.