Question

In the formula for carbon tetrahydride, CH4, the percent composition of all elements is:

75% C, 25% H

25% C, 75% H

81% C, 19% H

20% C, 80% H

Answer 1

C%=12/16*100=3/4*100=75%
H%=25%

Answer 2

The percentage composition if carbon tetrahydride is 75% of carbon and 25% of hydrogen.

Step-by-step explanation:

Molecular mass of carbon tetrahydride = 16 g/mol

Atomic mass of carbon = 12 g/mol

Atomic mass of hydrogen atom = 1 g/mol

Percentage of an element in a compound:

`\frac{\text{Number of atoms of element}* \text{Atomic mass of element}}{\text{molecular mass of element}}* 100`

Percentage of carbon:

`(1* 12 g/mol)/(16 g/mol)* 100=75\%`

Percentage of hydrogen:

`(4* 1g/mol)/(16 g/mol)* 100=25\%`

The percentage composition if carbon tetrahydride is 75% of carbon and 25% of hydrogen.