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 breaking.

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 rusting, burning, and digestion.

Front

Is rusting of iron a physical or chemical change?

Back

Rusting of iron is a chemical change.

Front

What is a sign that a chemical reaction has occurred?

Back

Formation of a gas, change in color, change in temperature, or the production of light are signs that a chemical reaction has occurred.

Front

When you break a cracker into pieces, is it a physical or chemical change?

Back

Breaking a cracker into pieces is a physical change.

Front

Is melting butter for popcorn a physical or chemical change?

Back

Melting butter for popcorn is a physical change.

Front

Which of the following is NOT an example of a physical change: crumpled paper, pencil sharpening, shrunken clothing, or rust?

Back

Rust is NOT an example of a physical change; it is a chemical change.

Front

What happens to the molecules during a physical change?

Back

During a physical change, the molecules may change their arrangement or state (solid, liquid, gas) but their chemical structure remains the same.

Front

What happens to the molecules during a chemical change?

Back

During a chemical change, the molecules rearrange to form new substances with different chemical properties.

Front

Give an example of a physical change that occurs when water freezes.

Back

When water freezes, it changes from liquid to solid (ice) without changing its chemical composition.