Success Homeschool

Year 8 Science · Physical and chemical change

Name: ______________________

Date: ____________

1. Which is a chemical change?
- ☐ (a) Ice melting
- ☐ (b) Paper being torn
- ☐ (c) Toast burning
- ☐ (d) Salt dissolving
2. In the equation iron + oxygen → iron oxide, what is iron oxide?
- ☐ (a) A product
- ☐ (b) A reactant
- ☐ (c) A catalyst
- ☐ (d) A mixture
3. Which observation does NOT by itself prove a chemical change?
- ☐ (a) A precipitate forms from two clear solutions
- ☐ (b) A new smell is produced
- ☐ (c) Light is given off
- ☐ (d) Bubbles form in boiling water
4. Which gas is produced when bicarbonate of soda reacts with vinegar?
- ☐ (a) Oxygen
- ☐ (b) Carbon dioxide
- ☐ (c) Hydrogen
- ☐ (d) Nitrogen
5. In a sealed container, what happens to the total mass during a chemical reaction?
- ☐ (a) It increases
- ☐ (b) It decreases
- ☐ (c) It stays the same
- ☐ (d) It becomes zero
6. Is a puddle drying up in the sun a physical or chemical change?
7. What name is given to an insoluble solid formed when two solutions react?
8. Substances present at the start of a reaction are called r________.

Answer sheet

1. Toast burning — Burning toast forms new substances such as carbon and gases.
2. A product — Substances on the right of the arrow are products.
3. Bubbles form in boiling water — Boiling water bubbles because liquid water turns to water vapour, a physical change.
4. Carbon dioxide — The reaction produces carbon dioxide gas.
5. It stays the same — Atoms are rearranged, not created or destroyed, so mass is conserved.
6. physical — Evaporation is a change of state; water vapour is still water.
7. precipitate — This solid is called a precipitate.
8. reactants — Starting substances are reactants.