Question

Gobar gas obtained by bacterial fermentation of animal refuse contains mainly methane. The heat of combustion of methane to $CO_{2}$ and water as gas is given by: $CH_{4}(g)+2O_{2}(g)\longrightarrow CO_{2}(g)+2H_{2}O(g)+809kJ$, How much gobar gas would have to be produced per day for a small village community of 100 families, if we assume that each family has to be supplied 20000 kJ of energy per day to meet all its needs and that the methane content in the gobar gas is 80 percent by weight.

Answer 1

Natural gas...............

Answer 2

Answer: 49.5kg

Explanation:

Biogas is a gaseous mixture of varied composition, generally composed of about 65% methane, 30% carbon dioxide (and traces of other gasss it is produced from anaerobic fermentation (in absence of air) of organic waste.

The given reaction is as follows

CH4+2O2==>CO2+2H2O+ 809KJ

Energy evolved is 809KJ

E=809KJ

The total energy required

=total consumption*no of families consuming

=20000*100

=2000000

=2*10^6KJ

According to the chemical reaction

809KJ of energy = 1 mole of CH4

= 16 gm of CH4

1 KJ energy = 16/809

Hence

2*10^6KJ = (16/809) *2*10^6

=39.6 kg

Methane content is given =80%

Weight of gobar gas

needed = (39.6/80) *100

=49.5kg

49.5 kg of gobar gas needs to be produced.