3. Find the composition of a sample of coal-gas from the data given (Bunsen.)

A portion of the residue was treated in an absorptiontube with H2SO4 containing excess of SO,, and then washed with KOH.

A part of the residue from B was then exploded in the eudiometer.

The remainder of the gas from A was then similarly

analysed.

All the volumes given in this example require to be reduced to some common temperature and pressure; taking o° C. and I m. pressure for standards, we have :

:

=

92'91

3'07.

After absorption by alkaline pyrogallate, remaining vol. 89.51, hence % of

59'75; hence

propylene, and benzene-vapour by SO

of these constituents

3'33 X 89'51 X 100

63'08 X 92'91

=

=

5'09.

=

(6308-59'75) X89'51X100

63'08 X 92'91

= 218.2

After absorption of CO2 produced

167'4; hence vol.

(2)

The incombustible residue of N from (2) is therefore,

Combustible gas

251 X 63'08 × 92.91

=

25'1 0'59 2451; and this con

sists of x vols. H + y vols. CH1 + 2 vols. CO.

=

=

D. Portion taken containing all the combustible gases 215; after addition of O 77'3; after addition of air 2004; after explosion 1662; hence contraction

34'2.

=

=

(1)

After absorption of CO2 produced, vol. = 152'9; hence

CO2

=

After addition of H to residue, vol. plosion 1848; hence second contraction

The contraction on explosion

= 153°2 per cent. of the volume

=

59.60 per cent. of the same.

Contraction due to CH4, CO, 39 X 59'75 X 89'51 X 100

=

and H, from C. (1),

1418 per cent. of

=

1532 1418

=

114 per cent. of vol.

25.1 X 63'08 X 92'91

original vol.; hence contraction due to ethylene, propylene,

and benzene,

of original gas.

=

Similarly, CO2 produced from CH, and CO, from C (2) 11.8 X 59'75 X 89'51 X 100

25.1 X 63.08 × 92.91

=

42'90 per cent., and so

vol. of CO2 produced from ethylene, propylene, and benzene, 59'60 42'90 16.70 per cent. of vol. of

The percentage of ethylene, propylene, and benzenevapour, present in the original gas is 5'09. (B).

=

Let x= percentage of C2H4, y percentage of C3H6, percentage of CH; then, from the equations :

and z =

C2H+3. O2 = 2CO2+ 2H2O.

2C3H6 +9. O2 = 6CO2 + 6H2O.

2C He+15. O2 = 12CO2+ 6H2O.

02

we have contraction 11'4 = 2x + 5y + §2.

and vol. of CO2 16'70 2x + 3y + 68;

=

=

From (5) and (6) 16'70 528 + 3y+6%

2.64 + y + z

31+6x1 y+2

}

}

(4)

(5)

(6)

1*36% of

203. Calculate the percentage composition of a sample of atmospheric air from the following numbers :