Available Answers

1. 1.

   Change is the law of nature and occur in our everyday life, at all times & in all places. Differentiate between the following changes with a suitable example.
   a) Desirable & undesirable change
   b) Periodic & non-periodic change
   c) Slow & fast change
   d) Natural & man-made change
   e)Reversible & irreversible change

2. 2.

   Differentiate between a physical change & a chemical change with reference to-
   a) Nature of change i.e temporary & reversible or permanent & irreversible.
   b) Formation of products
   c) Energy change taking place during the respective change.

3. 3.

   Give three reasons why melting of wax, is considered a physical change while burning of a candle, a chemical change.

4. 4.

   State the observations seen, when milk in a dish is kept aside for a few hours or more. Is the change which occurs-a physical change or a chemical change. Give reasons.

5. 5.

   State what is meant by the term-interconversion of matter. Is interconversion of matter a physical change or a chemical change.

6. 6.

   Ice kept in a beaker, slowly melts and turns into water. The water in the beaker on solidification i.e freezing turns back to ice. Give four reasons why the change from ice to water & water back to ice is considered a physical change.