(1) Nitrogen gas is present in air for nearly _____________

(2) ____________ is the most abundant inert gas present in air.

(3) Calcium cyanamide is used as _____________.

(4) Oxide of sulphur and nitrogen are _____________.

(1) Solar energy is connected into chemical energy during photosynthesis.

(2) Oxygen is colourless gas and neutral to litmus.

(3) Air pollutants do not affect the growth and yield of crops.

(4) By galvanisation, rusting can be prevented

(5) MnO2 acts as catalyst when potassium chlorate is heated at 420 K.

(1) Write the percentage composition of air.

(2) What is fuel?

(3)Name three greenhouse gases

(4) Name two air pollutants which affect our health.

(5) What is acid rain?

(1) What are fertilizers? Write the application of fertilizers

(2) Write the definitions of the following: (i) Nitrogen cycle (ii) Nitrogen fixation

(3) What happen when nitric acid reacts with calcium nitrate?

(4) Why is carbon dioxide known as a greenhouse gas?

(5) Explain ozone depletion.

(1) How can we control air pollution?

(2) Write four physical properties of oxygen gas

(3) What happens when oxygen reacts with each of the following: (i) Mg (ii) Ca (iii) H2 (iv) S

(4) Write the difference between photosynthesis and respiration

(5) Explain the oxygen cycle.

Nitrogen and oxygen

Hydrosphere

Sulphur dioxide

Brick manufacturing

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