Question

The heats of combustion of carbon, hydrogen and ethane are -94, -68.3 and -373kcal/mole respectively. The heat of formation of ethane in K.cal/mole is​

Answer 1

Answer:

H

2

+

2

1

O

2

⟶H

2

O+68.4........(i)

C

2

H

4

+3O

2

⟶2CO

2

+2H

2

O+3337.0......(ii)

C

2

H

6

+

2

7

O

2

⟶2CO

2

+3H

2

O+372.79.....(iii)

Onreversing eq (iii) we get

2CO

2

+3H

2

O+372.79⟶c

2

H

6

+

2

7

O

2

.....(iv)

On adding Eqs. (i),(ii),(iv) we get

C

2

H

4

+H

2

+372.79=C

2

H

6

+68.4+337

C

2

H

4

+H

2

⟶C

2

H

6

+32.61

ΔH=−32.61kcal