Science Physical and chemical changes Revision Test

Science Revision Test Physical and Chemical changes

Class 7

1. what is difference between physical and chemical changes? 

2.what is reversible and irreversible physical chamge

A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.

3.what kind of change is shown by Rusting of iron.

(a) Lime water turns milky on passing carbon dioxide gas into it.

(b) Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate

4. Lime water turns milky on passing carbon dioxide gas into it.

5. Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate.

6.A student took a solution of copper 

sulphate in a beaker and put a clean iron nail into it and left it for about an hour.

(a) What changes do you expect?

(b) Are these changes chemical in nature?

(c) Write a word equation for the chemical change, if any

7.Give an example of a chemical reaction for each of the following situations:

(a) A change in colour is observed.

(b) A gas is evolved.

(c) Sound is produced

8.If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.

(a) Do you think rust is different from iron?

(b) Can you change rust back into iron by some simple method?

(c) Do you think formation of rust from iron is a chemical change?

(d) Give two other examples of a similar type of change.

9.Fill in the blanks in the following

(a) Making sugar solution is a ____________ change.

(b) A physical change is generally____________.

(c) Grinding of wheat grain changes its size. It is a ____________ change.

(d) Iron benches kept in lawns and gardens get____________.

It is a _________ change because a new _________ is formed.

State whether the following statements are true or false:

(a) When a candle burns, both physical and chemical changes take place.

(b) Anaerobic bacteria digest animal waste and produce biogas.

(c) Ships suffer a lot of damage though they are painted.

(d) Stretching of rubber band is not a physical change.

10.State whether the following statements are true or false:

(a) When a candle burns, both physical and chemical changes take place.

(b) Anaerobic bacteria digest animal waste and produce biogas.

(c) Ships suffer a lot of damage though they are painted.

(d) Stretching of rubber band is not a physical change.