Use this worksheet to test students' understanding of the differences between physical and chemical properties and changes.

Let me work through this worksheet step by step.

Part 1: Classify the following as chemical change (cc), chemical property (cp), physical change (pc), or physical property (pp)

Let me think about each one:

1. Heat conductivity - This describes how well something conducts heat. It's a characteristic that can be observed without changing the substance. → Physical Property (pp)

2. Silver tarnishing - Tarnishing is when silver reacts with sulfur in the air to form silver sulfide. A new substance is formed. → Chemical Change (cc)

3. Malleability - The ability to be hammered into sheets. This is a characteristic, not a change. → Physical Property (pp)

4. Exploding gunpowder - Gunpowder undergoes a rapid chemical reaction producing new substances like gases and solids. → Chemical Change (cc)

5. Melting point - The temperature at which something melts is a measurable characteristic. → Physical Property (pp)

6. Sour milk - Milk sours because bacteria convert lactose into lactic acid, creating a new substance. → Chemical Change (cc)

7. Length of metal object - This is a measurable physical characteristic. → Physical Property (pp)

8. Brittleness - How easily something breaks is a physical characteristic. → Physical Property (pp)

9. Fermenting grapes - Fermentation converts sugars into alcohol and carbon dioxide through a chemical reaction. → Chemical Change (cc)

10. Rusting iron - Iron reacts with oxygen and water to form iron oxide, a completely new substance. → Chemical Change (cc)

11. Water freezing - Water changes from liquid to solid ice, but it's still H₂O throughout. → Physical Change (pc)

12. Wood burning - Burning wood produces ash, smoke, and gases—new substances are created. → Chemical Change (cc)

13. Breaking glass - Glass shatters into pieces but remains chemically the same material. → Physical Change (pc)

14. Acid rainwater - Acid rain forms when atmospheric gases dissolve in water to create acids, which is a chemical process. → Chemical Change (cc)

15. Ant oxidation - Oxidation involves a chemical reaction where the ant's body reacts with oxygen. → Chemical Change (cc)

16. Bitterness - This is a taste characteristic that can be observed without altering the substance itself. → Physical Property (pp)

17. Melting butter - Butter transitions from solid to liquid but maintains its chemical composition. → Physical Change (pc)

18. Boiling point - The temperature at which a substance boils is an inherent physical characteristic. → Physical Property (pp)

19. Rotting banana - Decomposition breaks down the banana into different substances through chemical reactions. → Chemical Change (cc)

20. Leaking faucet - Water simply flows out without any chemical transformation occurring. → Physical Change (pc)

Now I'm working through the second part, identifying whether each scenario represents a physical or chemical change. For the first one, aluminum being rolled into foil—that's just reshaping the metal without altering what it is, so that's physical. The second scenario describes a chemical reaction between baking soda and vinegar producing carbon dioxide gas, which means new substances are forming, making it chemical. The third one about hydrogen peroxide decomposing into water and oxygen also creates new substances, so that's chemical too.

For the fourth scenario with potassium permanganate dissolving in water—the color spreads throughout but the substance itself doesn't change chemically, it just disperses, so that's physical. The fifth one about photosynthesis is clearly chemical since plants are converting carbon dioxide and water into entirely new substances like glucose and oxygen.

The sixth scenario with sugar dissolving in water is tricky because while the sugar molecules separate and mix with water, they're still sugar molecules—no new substances form, so that's physical. Now I'm moving on to the third part where I need to identify whether each statement describes a physical or chemical property.

A magnet attracting iron is describing magnetic behavior, which is a physical property. Distilled water reacting with metals to produce hydrogen gas shows a chemical reaction happening, so that's a chemical property. Rusting due to moisture involves iron combining with oxygen to form a new substance, making it chemical. And turning yellow when exposed to light indicates a chemical change is occurring in the material.