Fill in the blanks: (a) Burning of wood and coal causes _________of air. (b) A liquid fuel used in homes is ___________.

Hydrogen can be considered a cleaner fuel because its burning produces water vapour which is non-polluting. However, due to explosive nature of hydrogen, its storage and transportation is difficult

(a) (i) and (ii) 

(i) interior  (ii) exterior  (iii) diameter  (iv) semicircle  (v) the chord  (vi) three

(a) Water is a conductor of electricity, so it can easily conduct electric current and cause danger of electric shocks or short-circuits. Therefore, water cannot be used to control the...

Burning of wood is a chemical change because wood on burning converted to new substances like ash (carbon), carbon dioxide gas, water vapour, heat and light. The change is irreversible....

Charcoal is considered a better fuel than wood because: (i) It has high calorific value. (ii) It does not produce any smoke. Disadvantages: (i) 1 kg of wood on destructive distillation produces only 0.25...

(a) sour, acids (b) natural (c) pink (d) neutralise, salt

Wood is a renewable source of energy. It is obtained by cutting trees. A new plant sapling usually takes more than 15 years to grow and mature into a tree....

a) Plant fibres are obtained from jute and cotton. b) Animals fibres are silk and wool

Charcoal is obtained from wood by destructive distillation of wood. Charcoal is considered a better fuel than wood because  (i) it has higher calorific value than wood.  (ii) it does not produce...