Give an example of a chemical reaction for each of the following situations:
- A change in colour is observed.
- A gas is evolved.
- Sound is produced.
- Formation of precipitate.
- Change of state from liquid to gas.
- Change of state from gas to liquid.
Answer:
- Reaction between copper sulphate soludon and zinc metal. The blue colour of the copper sulphate solution fades away and a red brown metallic copper is formed,
- Reaction between baking soda and vinegar. Baking soda on reaction with vinegar produces carbon dioxide.
- Burning of crackers.
- Reaction of silver nitrate and potassium chloride. A precipitate of silver chloride is formed.
- When water is heated above boiling point, it converts into vapours.
- Water droplets appear on the outside of a bottle containing cold water.