CLASS VII SCIENCE

Physical And Chemical Changes

Q.1 Fill in the blanks :

1. Photosynthesis is a _______________ change.

2. The micro-organisms which convert the dead plants and animals to humus are known as ______________.

3. The freezing point is ____ at which water freezes.

4. Lactobacillus bacterium helps in the formation of ______________.

5. Galvanization is the process of coating iron objects with the layer of ________ metal.

Q.2 Correct the following sentences by replacing the highlighted words :

1. Change in the physical properties of a substance is termed as chemical change.

Ans. ______________________________________________________________

2. Boiling is the process in which water turns to ice when cold enough (below 00C temperature.)

Ans. ______________________________________________________________

3. Formation of new substances by change in one or more substances is called physical change.

Ans. ______________________________________________________________

4. The process of deposition of brownish layer on iron when it is exposed to air and water is called polishing.

Ans. ______________________________________________________________

5. Melting is the process of formation of solid crystals from solution..It is a chemical change.

Ans. ______________________________________________________________