Tag: chemistry

The density of nitrogen gas prepared from the air is slightly greater than that of nitrogen prepared by chemical reaction from a compound of nitrogen, because aerial nitrogen contains a greater amount of $\displaystyle N _2$ molecules derived from $\displaystyle N-15$ isotope.
Note: Molecules containing $\displaystyle N-15$ isotope are heavier than molecules containing$\displaystyle N-14$ isotope as N atom has more number of neutrons.

$ { { (NH } _{ 2 }) } _{ 2 }{ Cr } _{ 2 }{ O } _{ 7 }\xrightarrow [ thermal\quad decomposition ]{ \Delta  } { Cr } _{ 2 }{ O } _{ 3 }+{ N } _{ 2 }+4{ H } _{ 2 }O\ N{ H } _{ 4 }{ NO } _{ 2 }\xrightarrow [ thermal\quad decomposition ]{ \Delta  } { N } _{ 2 }+2{ H } _{ 2 }O $

Main constituents of coal gas are; $CH _{4}, H _{2}$ and CO.

Coke obtained by destructive distillation of coal is not used for drinking purposes. But it is largely used as a reducing agent in the extraction of metals from their ores.

Among all, Kerosene have highest calorific value, hence it is used as aviation fuel in jet aeroplane.

Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium.

Natural gas mainly contains methane which on heating with water produces carbon monoxide and hydrogen. 

Petroleum is formed from dead organic matter. When a large amount of dead organism, usually zooplankton and algae are buried underneath sedimentary rock and subjected to intense heat and pressure after such a process the molecule turn into petroleum.Zooplankton is organism found in ocean and seas. This organism can't be found on land, on the rock, on the plant. So option "C "is the right answer.

The petroleum product used as fuel for stoves, lamps and jet aircraft is kerosene.