Air and Water

Essential for Life - Air & Water Worksheet-1

Multiple-Choice Question:

1. Which of the following holds the layer of air around the Earth?

(A) Earth’s gravity     (B) Moon’ gravity      (C) Sun’s gravity

2. What percentage (%) of oxygen is present in the air?

(A) 25%                        (B) 20%                       (C) 21%

Essential for Life - Air & Water Worksheet-3

Multiple-Choice Question:

1. Which of the following gas supports burning?

(A) Oxygen                 (B) Nitrogen               (C) Hydrogen

2. Which of the following gas is used by the green plants for the process of photosynthesis?

(A) Hydrogen             (B) Carbon dioxide   (C) Helium

Essential for Life - Air & Water Worksheet-4

12. True/False

a.      Graphite is used in making light bulbs and fluorescent tubes.

b.      Air is a mixture of several gases.

c.      The rate of evaporation is faster in winter as compared to summer.

d.      It is very easy to separate soluble impurities from the solution as compared to insoluble impurities.

e.      Boiling the drinking water for 30 seconds can kill the germs and make it germ free.

f.       The rate of evaporation decreases with increase in temperature.