Comprehensive guide for students to differentiate between physical traits like malleability and chemical behaviors like combustion.

The image you've uploaded is a completed worksheet titled "Chemical and Physical Properties" from a science course (SNC1D0). The task asks students to classify each given description as either a physical property or a chemical property, and then identify the type of property (e.g., color, density, reactivity, etc.).

Below is a detailed explanation of how each answer was determined, based on scientific principles:

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🔍 Definitions:

- Physical Property: A characteristic that can be observed or measured without changing the substance’s chemical identity. Examples: color, state, density, malleability, melting point.

- Chemical Property: A characteristic that describes how a substance interacts with other substances to form new substances. It involves a chemical change. Examples: flammability, reactivity with acids, toxicity.

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✔ Explanation of Each Answer:

1. The sulphur is yellow.
- Physical – Color is a physical property.
- Type: *Colour*

2. Iron reacts with sulphur to give heat and a flame.
- Chemical – This describes a chemical reaction forming iron sulfide.
- Type: *Combustibility; Reaction* (Note: This is more accurately a reaction rather than combustibility, since it's not burning in oxygen.)

3. Baking soda with acid produces bubbles of gas.
- Chemical – CO₂ gas is produced via a chemical reaction (acid-base).
- Type: *Reaction with acid*

4. Metal can be rolled into flat sheets.
- Physical – Malleability is a physical property.
- Type: *Malleability*

5. Oxygen is colourless, odourless and tasteless.
- Physical – These are sensory properties observable without chemical change.
- Type: *Colour, odour, taste*

6. Nitrogen dioxide gas has a choking smell.
- Physical – Odor is a physical property.
- Type: *Odour*

7. Helium is less dense than air, so a helium balloon floats.
- Physical – Density comparison is physical.
- Type: *Density*

8. Wax candle burns in oxygen.
- Chemical – Combustion (burning) is a chemical change.
- Type: *Combustibility*

9. An apple rots due to fungi.
- Chemical – Rotting involves decomposition by microorganisms, a chemical change.
- Type: *Reaction*

10. Mercury metal is a liquid.
- Physical – State of matter is a physical property.
- Type: *State*

11. Iodine gas is purple.
- Physical – Color is a physical property.
- Type: *Colour*

12. Hydrofluoric acid is poisonous.
- Chemical – Toxicity refers to how it reacts with biological systems (chemical interaction).
- Type: *Reaction*

13. Gold is a shiny metal.
- Physical – Shine (lustre) is a physical characteristic.
- Type: *Lustre*

14. Cesium is the only other gold-coloured metal.
- Physical – Color is a physical property.
- Type: *Colour*

15. Potassium burns with a purple flame to make a white powder.
- Chemical – Burning (oxidation) forms potassium oxide, a new substance.
- Type: *Combustibility*

16. Copper nitrate is a blue crystal.
- Physical – Color and crystal structure are physical traits.
- Type: *Colour, crystal form*

17. Two colourless solutions mix to give a yellow solid precipitate.
- Chemical – Formation of a precipitate indicates a chemical reaction.
- Type: *Reaction*

18. Copper can be stretched into a thin wire.
- Physical – Ductility is a physical property.
- Type: *Ductility*

19. Copper metal reacts with nitric acid to make a brown gas.
- Chemical – Reaction with acid producing nitrogen dioxide (brown gas) is a chemical change.
- Type: *Reaction with acid*

20. Salt, sodium chloride, is a white crystal that melts at 801 °C.
- Physical – Color, crystal form, and melting point are all physical properties.
- Type: *Colour, crystal form, melting point*

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📌 Summary of Key Concepts:

- Physical properties describe appearance or behavior without changing the substance.
- Chemical properties involve how a substance interacts with others to form new substances.
- Look for keywords like:
- Physical: color, state, odor, density, melting point, malleability, ductility, solubility.
- Chemical: reacts with, burns, rusts, decomposes, toxic, combustible.

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✔ Conclusion:
The answers provided in red are correct and reflect accurate classifications based on standard scientific definitions. The worksheet demonstrates a solid understanding of the difference between physical and chemical properties.

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