Tag: chemistry

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Multiple choice chemistry rocks and minerals coal and its products study of coal coal

Naphthalene which is used to repel moths and other insects is obtained from:

  1. Coal Tar

  2. Petroleum

  3. Coke

  4. Paraffin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Naphthalene which is used to repel moths and other insects is obtained from coal tar.
Coal tar is a thick black liquid. It is obtained from the distillation of bituminous coal. It contains benzene, naphthalene, phenols, aniline, and many other organic chemicals.

Multiple choice chemistry rocks and minerals coal and its products study of coal coal

Coal can be used as a:

  1. purifier

  2. fuel

  3. insecticide

  4. fertilizer
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Coal is a fossil fuel that forms when dead plant matter is converted into peat, which in turn is converted into lignite, then sub-bituminous coal, after that bituminous coal, and lastly anthracite.The most significant uses of coal are in electricity generation, steel production, cement manufacturing and as a liquid fuel.

Multiple choice chemistry rocks and minerals coal and its products study of coal coal

One which is known as a nonrenewable energy is:

  1. tides

  2. coal

  3. wind

  4. boimass
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A non-renewable resource is a resource of economic value that cannot be readily replaced by natural means on a level equal to its consumption. Most fossil fuels, such as oil, natural gas and coal are considered nonrenewable resources in that their use is not sustainable because their formation takes billions of years.

Multiple choice chemistry rocks and minerals coal and its products study of coal coal

Coal tar is a main source of:

  1. Aromatic compounds

  2. Aliphatic compounds

  3. Cyclo alkanes

  4. Hetero cyclic compounds
Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation

Coal tar is obtained by cooling the gas that is formed during the destructive distillation of coal to approximately ambient temperature. It is a black, viscous liquid composed primarily of a complex mixture of condensed-ring aromatic hydrocarbons.

These are mixtures of phenols, polycyclic compounds and Heterocyclic compounds.

Multiple choice chemistry rocks and minerals coal and its products study of coal coal

Coal tar which is main source of organic compounds is obtained as by product during?

  1. destructive distillation of wood

  2. destructive distillation of bones

  3. destructive distillation of coal

  4. all of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Coal tar which is main source of organic compounds is obtained as by product during the destructive distillation of coal.

Coal tar is a thick black liquid which is the  by-product of the production of coal gas and coke by the ddestructive distillation of coal which  contains benzene, naphthalene. Coal tar is used for medical and industrial purposes. However, coal is also known as cutar.

Hence option C is correct.

Multiple choice chemistry rocks and minerals coal and its products study of coal coal

How much coal is needed to supply enough electricity to light ten 100-watt bulbs for about an hour?

  1. 1 pound

  2. 10 pounds

  3. 50 pounds

  4. 20 pounds
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

100 watts = 0.1 KW


For 1 bulb 0.1 KW of power is required, for 10 bulbs that turn out to be 1KW.
Now 10 bulbs have to light for 1 hour that will be 1 KW multiplied by 1 hour = 1 KW

The thermal energy of coal is 6,150 KW/ton, only 40% of the thermal energy of the coal is converted to electricity. so the electricity converted per ton of coal is 0.4 * 6,150 = 2,460 KW/ton.

Number of tons of coal burned for 10 light bulbs for one hour = 1 KW / 2,460KW/ton = 0.0004065 tons 

Multiplying by 2000 pound/ton we get 0.81300 $\approx$ 1 pounds.