Tag: chemistry

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Multiple choice chemistry occurrence of carbon compounds in nature substances, objects and energy alternative fuels and energy sources alternative sources of energy

Sewage gases are produced by by the decomposition of :

  1. organic household

  2. industrial wastes

  3. both A and B

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sewer gas is a complex mixture of toxic and nontoxic gases produced and collected in sewage systems by the decomposition of organic household or industrial wastes, typical components of sewage. Sewer gases may include hydrogen sulfide, ammonia, methane, esters, carbon monoxide, sulfur dioxide and nitrogen oxides.

Multiple choice chemistry occurrence of carbon compounds in nature substances, objects and energy alternative fuels and energy sources alternative sources of energy

 Which of the following is/are the advantage(s) of using hydrogen as an automobile fuel?

  1. The amount of energy released per unit weight of the fuel is very low.
  2. The combustion hydrogen does not produce polluting emissions of CO, $CO _2$, oxides of nitrogen, and sulphur, aldehydes etc.

  3. The technology required for use of hydrogen fuel is simple and cost effective.

  4. The fuel cells using catalytic combustion of hydrogen have efficiency of 70-80 percent.
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

The following are the advantages of using hydrogen as an automobile fuel.
The amount of energy released per unit weight of the fuel is very high.
The combustion hydrogen does not produce polluting emissions of CO, $CO _2$, oxides of nitrogen, and sulphur, aldehydes etc. Here, combustion product of hydrogen is water with few traces of nitrogen oxides. So no pollution is caused.
The technology required for use of hydrogen fuel is simple and cost effective.
The fuel cells using catalytic combustion of hydrogen have efficiency of 70-80 percent.

Multiple choice chemistry occurrence of carbon compounds in nature substances, objects and energy alternative fuels and energy sources alternative sources of energy

Methane gas is an organic fuel obtained from the sources mentioned here. Which of the following is not a correct source?

  1. Coal gas

  2. Molasses

  3. Natural gas

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

Molasses is a factory waste from sugar industry. It does not contain any traces of methane. So, methane is not obtained from molasses.

Multiple choice chemistry occurrence of carbon compounds in nature substances, objects and energy alternative fuels and energy sources alternative sources of energy

How wars and attacks can act as reason for energy crisis?

  1. Wars between countries can also hamper supply of energy specially if it happens in Middle East countries like Saudi Arabia, Iraq, Iran, Kuwait, UAE or Qatar

  2. It will attract MNCs to invest int those countries

  3. It will cause the death of people

  4. It will decrease the price of fossil fuels
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Wars between countries can also hamper supply of energy specially if it happens in Middle East countries like Saudi Arabia, Iraq, Iran, Kuwait, UAE or Qatar. Thats what happened during 1990 Gulf war when price of oil reached its peak causing global shortages and created major problem for energy consumers.

Multiple choice chemistry occurrence of carbon compounds in nature substances, objects and energy alternative fuels and energy sources alternative sources of energy

Which of the following is not true about Biogas? 

  1. It contains methane

  2. Burns without smoke

  3. Leaves ash behind

  4. Produced by anaerobic decomposition of animal and plant waste
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Higher the methane content, higher the calorific value. Pure $CH _4$ has a Gross Calorific Value of 39.8 $MJ/m^3$. the rate of combustion of biogas is quite high as it is produced by anaerobic decomposition of animal and plant waste.
It does not leave any ash behind after burning as cow dung and other organic matter is used in the preparation of biogas.

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

The petroleum product that has replaced coal-tar for metalling the road is __________.

  1. peat

  2. bitumen

  3. lignite

  4. anthracite
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Bitumen is an oil-based substance. It is a semi-solid hydrocarbon product produced by removing the lighter fractions (such as liquid petroleum gas, petrol, and diesel) from heavy crude oil during the refining process. 

As such, it is correctly known as refined bitumen. It is used as a road paving material. The vast majority of refined bitumen is used in construction: primarily as a constituent of products used in paving and roofing applications. According to the requirements of the end-use bitumen is produced to specification.

So, the correct option is $B$
Multiple choice chemistry rocks and minerals coal and its products study of coal coal

Coal can be formed from ____________.

  1. sunlight

  2. steam

  3. fossils

  4. plants
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When dead plants get buried into the bottom of the soil they are slowly converted into coal due to high pressure and high temperature. Heat and pressure produced chemical and physical changes in the plant layers which forced out oxygen and left rich carbon deposits. In time, material that had been plants became coal.

Coal is formed from plants and animals that died millions of years ago.

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

The characteristic of coal is ___________.

  1. toughness

  2. black in colour

  3. porous nature

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

Since coal is a form of sedimentary rock, it's is hard and porous. It is black due to its prime composition of carbon, compressed at high temperature and pressure.