Grade 8 SUB : Science CH 2 Coal and Petroleum W.B. Work

 

1.	Fill in the blanks.
	a.	Brass is a __________ resource. (natural/ human-made)
	Ans.	human-made
	b.	The main constituent of natural gas is _________________ .(methane/propane)
	Ans.	methane
	c.	__________ variety of coal contains 50-70% content of carbon. (Peat/ Lignite)
	Ans.	Lignite
	d.	Naphthalene is used as a __________ repellent. (mosquito/ moth)
	Ans.	moth
2.	Match the column ‘A’ with column ‘B’.
	Column ‘A’			Column ‘B’
	a.	Kerosene		i.	Fuel for cooking
	b.	Coal gas		ii.	Manufacture of fertilisers
	c.	LPG		iii.	Used in street lighting
	d.	Hydrogen		iv.	Fuel in lamps
	Ans.	a® iv,b ®iii, c ®i, d ®ii
3.	Complete the analogy.
	a.	________ : Renewable natural resource : : Coal : Non-renewable natural resource
	Ans.	Solar energy/ Wind energy/ Tidal energy
	b.	Coke: Reducing agent : : ________ : Cleansing agent
	Ans.	Ammoniacal liquor/ Liquor ammonia
	c.	________ : Manufacture of paints : : Gasoline : Solvent for dry cleaning
	Ans.	Asphalt/ Bitumen
	d.	________ : Phenol : : Petrochemical : Vinyl chloride
	Ans.	Coal tar
4.	Answer the following questions in one sentence.
	a.	What is inexhaustible natural resource?
	Ans.	Resources that are present in unlimited quantity in nature and are not likely to be exhausted by human activities or consumption are called inexhaustible natural resources.
	b.	What are petrochemicals?
	Ans.	Chemicals derived from petroleum or natural gas are called petrochemicals.
	c.	Name the hydrocarbons that are present in natural gas.
	Ans.	Methane, Ethane, Butane and Propane
5.	Answer the following questions in 2-3 sentences.
	a.	Name the gas produced using coke that is a mixture of:
		i.	carbon monoxide and hydrogen.
		ii.	carbon monoxide and nitrogen.
	Ans.	i.	Water gas
		ii.	Producer gas
	b.	What happens to the components of petroleum with higher and lower boiling points in the fractionating column?
	Ans.	·         The components with higher boiling points will condense at the lower levels of the fractionating column. ·         The components with lower boiling points will liquefy towards the top of the fractionating column.
	c.	State the advice given by the Petroleum Conservation Research Association to conserve energy.
	Ans.	Petroleum Conservation Research Association advises people to: ·         drive at a constant and moderate speed ·         switch off the car engine at signals ·         maintain correct air pressure in the vehicle’s tyre ·         regularly service the vehicles for maximum fuel efficiency
6.	Picture Study
	The given picture is of a fossil fuel.Observe the given picture and answer the following questions.
	a.	Identify the fossil fuel shown in the picture.
	Ans.	Coal
	b.	What is the first step in the formation of this fossil fuel?
	Ans.	Formation of peat
	c.	Which variety of this fossil fuel is used for residential and commercial space heating?
	Ans.	Anthracite
7.	Fun Time
	Complete the given crossword.
	Across			Down
	3. A variety of coal which contains 85-90% of carbon. (ANTHRACITE)			1. A petroleum product used in the manufacture of petrochemicals. (NAPHTHA)
	5. Petroleum formed millions of years ago beneath the Earth’s surface gets trapped in this rock. (RESERVOIR ROCK)			2. A greenhouse gas. (NITROUS OXIDE)
	6. High levels of this poisonous gas in the air can lead to a fatal condition where supply of oxygen to blood cells is cut off. (CARBON MONOXIDE)			4. It is a process of conversion of dead vegetation into coal. (CARBONISATION)
	7. Another term used for the petroleum products obtained after refining. (FRACTIONS)
8.	Challenge Time
	We get a pungent smell when there is a CNG leakage even though natural gas is odourless. Why?
Ans.	Any accidental leakage can cause an explosion. If the gas leaks in any closed space then on lighting a matchstick, it will burst into flames causing a fire in the house and can cause serious burn injuries. In order to prevent this, a chemical ethyl mercaptan is added to CNG which helps in detection of the leakage because of the smell imparted.
9.	Practical Learning
	Hydrogen is used as a rocket fuel. It yields almost double the energy provided by jet fuels yet it is not used as a domestic fuel. What could be the possible reason for this?
Ans.	·         It is not easily available and cost of production is high. ·         It is not easy to store. ·         It is highly explosive. ·         It does not burn at a slow rate. ·         It is difficult to store and transport and costs more than natural gas.