Question

which compound has molecular mass 100​

Answer 1

Answer:

The molar mass is the mass of a given chemical element or chemical compound (g) divided by the amount of substance (mol). The molar mass of a compound can be calculated by adding the standard atomic masses (in g/mol) of the constituent atoms.

Answer 2

Explanation:

Let the mass of unknown compound be 100 g.

Given that the compound contains 80% of carbon and 20% of hydrogen.

Therefore, weight of carbon in the compound =80g

weight of hydrogen in the compound =20g

Molecular weight of carbon =12g

Molecular weight of hydrogen =1g

∴ moles of carbon in the compound =

12

80

=6.67

Moles of hydrogen in the compound =

1

20

=20

Ratio of no. of moles of carbon to no. of moles of hydrogen-

No. of moles of carbon : no. of moles of hydrogen =6.67:20≈1:3

∴ 3 moles of hydrogen are present in the compound for 1 mole of carbon.

Hence, the empirical formula of the compound is CH

3

.

empirical mass=15 g/mol

Molecular formula =(CH

3

)

n

whereas,

n=

empirical mass

molecular mass

=

15

30

=2

Thus, the molecular formula of the compoud is C

2

H

6