English Medium कक्षा १० - CBSE Question Bank Solutions for Science

In addition to wheat plants, a crop field ecosystem has organisms such as snake, peacock, eagle and mice. If the wheat plants are sprayed with pesticides periodically, which of the following will have the minimum concentration of pesticides in the body?
(a) snake
(b) eagle
(c) mice
(d) peacock

Translate the following statement into chemical equation and then balance the equation:

Phosphorus burns in oxygen to give phosphorus pentoxide.

Translate the following statement into chemical equation and then balance the equation:

Carbon disulphide burns in air to give carbon dioxide and sulphur dioxide.

The ten per cent law is associated with
(a) transfer of energy from various trophic levels to decomposers in a food chain
(b) transfer of ATP energy into muscular energy
(c) transfer of chemical energy from one organism to another
(d) transfer of sun's energy to the organisms called producers.

Translate the following statement into chemical equation and then balance the equation:

Aluminium metal replaces iron from ferric oxide, Fe₂O₃, giving aluminium oxide and iron.

The harmful chemical which is accumulating in human beings through food chain is :
(a) benzenehexachloride
(b) dichlorodiphenyltrichloroethane
(c) chlorofluorocarbon
(d) abscisic acid

Translate the following statement into chemical equation and then balance the equation:

Barium chloride reacts with zinc sulphate to give zinc chloride and barium sulphate.

The surface of water in a lake appears green due to a layer of tiny free-floating organisms X on its surface. The lake water also contains organisms like water beetle, fish and tadpole. The sun shines over the lake water and provides energy for the functioning of this lake ecosystem.
(a) What could organisms X be?
(b) Write a food chain comprising of all the four organisms mentioned.
(c) What is the general name of the food chains like the one written above?
(d) Name (i) secondary consumer (ii) producer (iii) tertiary consumer, and (iv) primary consumer, in the above food chain.
(e) If the tertiary consumer gets 0.2 J of energy from the secondary consumer, then how much energy was radiated by the sun to the producer?

Give one example of a chemical reaction.

A forest ecosystem having a lot of green plants has some foxes, lions and rabbits in it.
(a) Write a food chain comprising all the four organisms mentioned above.
(b) Name (i) one herbivore, and (ii) two carnivores, in this food chain.
(c) Name the link which is a predator as well as a prey.
(d) Name (i) second trophic level, and (ii) third trophic level.
(e) Which link of this food chain can feed on second trophic level as well as third trophic level, independently?
(f) If the sun provides 1000 J of energy to the plants, then how much energy will be transferred to fox through the food chain.

Complete and balance the following equation:

NaOH  + ............     Na₂ SO₄    + H₂O

A food chain consists of fish, larvae, phytoplanktons and birds. The level of pesticides in water in which the fish, larvae and phytoplanktons live is quite high.
(a) In which organisms the pesticides enter from the polluted water? What is this level of organisms known as?

A food chain consists of fish, larvae, phytoplanktons and birds. The level of pesticides in water in which the fish, larvae and phytoplanktons live is quite high.                                             

Which organism will have the maximum amount of pesticides accumulated through the food chain? What is this process known as?

Complete and balance the following equation:

CA (OH)₂  +  .............          CaCO₃    +   H₂O

A food chain consists of fish, larvae, phytoplanktons and birds. The level of pesticides in water in which the fish, larvae and phytoplanktons live is quite high.

Write the food chain comprising all the organisms mentioned above.

A food chain consists of fish, larvae, phytoplanktons and birds. The level of pesticides in water in which the fish, larvae and phytoplanktons live is quite high.

Which other organism you could write in place of bird in the above food chain?

Correct and balance the following equation:
Ca   +   H₂O     CaOH   +   H

Correct and balance the following equation:

N    +   H     NH₃

Write complete balanced equation for the following reaction:

Calcium (solid) + water (liquid)  Calcium Hydroxide (solution) + Hydrogen (gas)

Write complete balanced equation for the following reaction:

Sulphur dioxide (gas) + Oxgyen (gas)   Sulphur trioxide (gas)