Chemical and Physical Changes Concepts

This tutorial explains the differences between physical and chemical changes. Physical changes involve no new substances and are often reversible, like melting ice. Chemical changes result in new substances with different properties and are irreversible, like burning wood. Examples of each type are provided, and the tutorial concludes with a comparison of the two.

Which of the following is an example of a change that involves one or more substances?

• Souring of milk

• Boiling of water

• Cutting of paper

• Melting of ice

What happens to the chemical composition of a substance during a physical change?

• It changes completely

• It remains the same

• It becomes unstable

• It forms a new substance

Which of the following is NOT an example of a physical change?

• Burning of wood

• Glowing of an electric bulb

• Sublimation of iodine

• Melting of wax

What is a characteristic of a chemical change?

• It involves no energy change

• It is reversible

• It is temporary

• It forms new substances

Which of the following is an example of a chemical change?

• Freezing of water

• Photosynthesis in plants

• Cutting of vegetables

• Formation of vapors

What is released when wood is burned?

• No energy

• Only light

• Only heat

• Heat and light

How does a physical change differ from a chemical change in terms of energy?

• Chemical change always absorbs energy

• Physical change always releases energy

• Chemical change never involves energy

• Physical change may or may not involve energy

Which type of change is usually referred to as a chemical reaction?

• Both physical and chemical changes

• Chemical change

• Neither physical nor chemical changes

• Physical change

What is the nature of a chemical change?

• Temporary and reversible

• Permanent and irreversible

• Permanent and reversible

• Temporary and irreversible

What will the next tutorial introduce?

• Physical changes

• Metabolic reactions

• Chemical reactions

• Energy changes