What percentage of carbon is contained by 0 2 gram of hydrocarbon which gives 0 506 gram of carbon dioxide - Chemistry - Basic Concepts in Chemistry

Question

What percentage of carbon is contained by 0 2 gram of hydrocarbon
which gives 0 506 gram of carbon dioxide on complete combustion

Yasodharan · Accepted Answer

Dear Student,

CxHy

+

O2

(excess)

→

CO2

+

H2O

0

44g

0

88

g

1

8g

44

g

of

CO2

contains

12

g

of

CTherefore,

0

88g

of

CO2

contains

1244×

0

88

=

0

24

g

of

CNow,

18g

of

H2O

contains

2g

of

HTherefore,

1

8

g

of

water

will

contain

218×

1

8

=

0

2

g

of

HNow

according

to

Law

of

Conservation

of

Mass,Mass

of

reactant

=

Mass

of

productSince

O2

is

in

excess,

we

can

ignore

it

and

since

only

C

and

H

are

present

in

the

reactant

we

will

only

add

amount

of

C

and

H

in

the

product

0

44

g

=

0

24

g

+

0

2

g

0

44

g

=

0

44

gThe
amount of carbon in 0 506 gm CO2 = 12/44 x 0 506 = 0 138
gm

similarly amount of H in 0 1014 gm of H2O = 2/ 18 x 0
1014 = 0 011 gm

As the compound completely burns giving only CO2 and
H2O in presence of oxygen,

Here, total amount of carbon and hydrogen in compound = 0 138 + 0
011 = 0 149 gm

Hence , %age composition of Hydrogen = 0 011/ 0 149x 100 = 7 38
%

Similarly %age of Carbon = 0 138/ 0 149 x 100 = 92 61 %

Regards

Note: The gram of water is not given in question statement hence
the computation are performed using standard value of water
mass

What percentage of carbon is contained by 0.2 gram of hydrocarbon which gives 0.506 gram of carbon dioxide on complete combustion