Name the various modes of waste disposal.

Name the wastes which are generated in your house daily. What measures would you take for their disposal?

Every household produces a lot of material A daily. In one of the methods of disposal B, material A is burned at a very high temperature of about 1000°C in a structure called C. During this process, the organic matter present is removed as D and E whereas F is left behind (which can be dumped in a landfill site).

(a) What is material A

(b) Name the method of disposal B.

(c) What is structure C known as?

(d) What are

(i) D

(ii) E, and

(iii) F?

(e) This method is especially suitable for the disposal of materials produced by certain institution. Name such institutions.

The percentage of solar radiation absorbed by all the green plants for the process of photosynthesis is about

In the following groups of materials, which group (s) contains only non-biodegradable items?

i. Wood, paper, leather

ii. Polythene, detergent, PVC

iii. Plastic, detergent, grass

iv. Plastic, bakelite, DDT

After the examinations Rakesh with his friends went on a picnic to a nearby park. All friends carried cooked food packed in plastic bags or plastic cans. After eating the food some friends collected the leftover food and plastic bags etc. and planned to dispose them off by burning. Rakesh immediately checked them and suggested to segregate the leftover food and peels of fruits from the plastic materials and respectively dispose them off separately in the green and red dustbins placed in the corner of the park.

(a) In your opinion, is burning plastic an eco-friendly method of waste disposal? Why? State the advantage of the method suggested by Rakesh.

(b) How can we contribute in maintaining the parks and roads neat and clean?

What makes the earths atmosphere a heterogeneous mixture?

Write the name and formula of a molecule made up of three atoms of oxygen.

Write the electron dot structure of ethane molecule, C₂H₆.