Friday, August 10, 2012

8th Science CBSE Test paper Solved Chapter 5 Coal and Petroleum

8th  Science CBSE Test paper Solved Chapter 5 Coal and Petroleum
1 mark Questions
1. The slow process of conversion of dead vegetation into coal is called ________
2.Naphthalene balls are obtained from __________
Ans: Coal tar
3.A petroleum product known as __________ is used for metalling the roads.
Ans: Bitumen/Asphalt
4. Natural gas is stored under high pressure as _________
Ans: CNG
5.__________ is a cleaner fuel.
Ans: CNG
6.---------is used as a fuel in jet aircraft.
Ans: Kerosene oil
7.------- is the petroleum gas which has been liquefied under pressure.
Ans: LPG
8. The major constituent of CNG is ___________and LPG is ---------
Ans: Methane ,Butane
9. ___________ is the best known reinforcing agent in rubber industry
Ans: Carbon black
10.The quality of gasoline is generally expressed in terms of _________
 Ans: Calorific value 
 2 marks Questions
1. How natural gas is transported from place to place?
Ans: Natural gas is transported from place to place through pipeline
2. Name three variety of coal.
Ans: Anthracite, Bituminous and Lignite
3. Why do we need to conserve fuel judiciously?
Ans: The consumption of fuel increases rapidly due to growth of population and these fuels cannot replenish easily we feel to conserve it by using economically and wisely.
4. Distinguish between exhaustible & inexhaustible natural resources. Give examples.
Ans: The resource those are available for limited period for use is called exhaustible natural resources like Coal, petroleum, Natural gas etc.
The resource that are available for unlimited period for use is called inexhaustible natural resources like wind ,water, sunlight etc
5. Name a product of coal which is used in the manufacture of steel. What are its characteristics? 
 Ans: Coke is a product of coal which is used in the manufacture of steel. It contain 98% carbon
3 mark Questions.
1. Why petroleum is also called black gold?
Ans: The constituents of petroleum are very useful for us. Due to its great commercial importance, petroleum is also called 'black gold'.
2.What is petroleum? How different fractions of petroleum are separated?
Ans: A dark coloured florescent liquid which occur deep inside the earth is called petroleum.
The process of separating various constituents / fractions of petroleum  is fractional distillation in fractionating columns.
3. Describe the advantages of using natural gas.
Ans:   (a) Burn with smoke less flame
(b) Do not leave ash
(c) Having high calorific value about 55kgJ/g
4. We often use LPG in our home for cooking. How you detect the leakage of gas? What substance is added to LPG for this purpose?
Ans: A gas like hydrogen sulphide which smells like rotten eggs is added to natural gas.
5. What are the harmful effects of burning fossil fuels? How it affect the environment?
Ans: (a)the increases in carbon dioxide lead to large scale environmental damage such as acid rain.
(b)Carbon dioxide that the remains in the upper atmosphere will tend to trap sun rays, which is called the "greenhouse effect" and leads to global warming.
(c) people can become sick from breathing carbon monoxide emitted from vehicles.
(d) Burning of coal releases sulfur and nitrogen, which help form acid rain
6. Explain petrochemicals?
Ans: Many useful substances are obtained from petroleum and natural gas. These are termed as Petrochemicals. These are used in the manufacture of detergents, fibres (like polyester, nylon, acrylic), polythene and other man-made plastics. 
5 marks Questions
1. What are the different constituents of petroleum and their uses?
Fraction                       Uses   
Petroleum Gas                        Fuel for home (LPG)
Petrol                           Motor fuel
Kerosene                     Fuel for stove and jet aircrafts.
Diesel                          Fuel for heavy motor vehicles.
Lubricating oil              Lubrication
Fuel Oil                                    Fuel for Power Stations and Ship
Paraffin wax               Candles, Vaseline
Bitumen                       Paints, road surfacing
2. What do you mean by PCRA? What are their tips?
Ans: In india, the Petroleum Conservation Research Association(PCRA) advises people how to save petrol/diesel while driving. Their tips are
● Drive at a constant and moderate speed as far as possible.
● Switch off the engine at traffic lights or a t a place where you have to wait.
● Ensure correct tyre pressure.
● Ensure regular maintenance of the vehicle.
3. We know that coal is formed from dead vegetation. Explain the process of formation of coal.
Ans: Three hundred and fifty million years ago, some plants grew into giant ferns and mosses. These plants got buried into the bottom of the soil and deposited as fossil due to heat and pressure. The decaying plants were pressed and coal was formed.
4. Name, constituent of petroleum which is used for following purposes.
 (i) To make candles. 
(ii) A solvent for dry cleaning
(iii) For surfacing roads.
(iv) Jet engine fuel.
(v) For lubrication.
Ans: (1) Parafin wax
        (iv) kerosene
       (v)lubricating Oil
CBSE 8th Science Ch.5.Coal and Petroleum Solved questions

No comments:

Post a Comment