Chemical and Physical Changes

When does a physical change occur?

• when molecules combine to form a compound

• when the size, shape, or state of matter changes

• when the chemicals in an object change permanently

When does a chemical change occur?

• when molecules combine to form a compound

• when the size, shape, or state of matter changes

• when the chemicals in an object change permanently

True or false: Chemical changes can be easily reversed.

• True

• False

If a substance changes color, what has most likely happened?

• A physical change has taken place.

• A chemical change has taken place.

• Nothing has happened.

Stepping on a bag of potato chips would cause which type of change?

• thermal

• physical

• chemical

Which of the following is a clue that a chemical change has taken place?

• A gas forms when the change takes place.

• The substance is smaller than it was before the change took place.

• The substance has been shaken up.

What is the difference between a physical and chemical change?

• A physical change only occurs in liquids, but a chemical change can happen in a solid, liquid, or gas.

• A physical change is when the size, shape, or state of matter changes. A chemical change is when the molecules of matter change to form a new substance.

• A chemical change is when the size, shape, or state of matter changes. A physical change is when the molecules of matter change to form a new substance.