Give a reason for each of the following. 1. Burning of fuel is a desirable change. 2. Rotation of the Earth is a periodic change. 3. Melting of butter is a physical change. 4. Generally physical changes are easier to reverse while chemical changes are not 5. Boiling of water is a physical change but boiling of egg is a chemical change.
Answers
Answer:
Burning Of Fuel is a Chemical Change.
Answer:
1 . The burning of fuels like wood, coal or petrol is both desirable and undesirable change. The burning of fuels produce heat which is desirable but the burning also produce smoke. It pollutes the atmosphere and is undesirable.
Solution.
Physical change
Chemical change
2 . Rotation of earth happens during a period of time i.e. 24 hrs. therefore, rotation of earth is a periodic change.
3 . When you first apply heat to a solid substance like butter, it melts into a liquid. This is a physical change.
4 . Physical changes do not make a new substance.
Since objects do not become a different substance during a physical change, it is usually easy to reverse the change. For example, if you dissolve sugar in water you can easily reverse the change by evaporating the water from the solution.
5 . Boiling of egg a chemical change.In case of boiling egg the composition of egg is irreversible. New substance is formed so it irreversible. ... Boiling of water to form water vapour is a physical change. There is only a change in state of matter but no chemical changes has occurred.