Question

The analysis of 2.12 of a compound gave 0.33 of carbon, 1.82 of the same compound gave 1.53 of sulphur. Calculate the emperical formula

Answer 1

CS₂

Step-by-step explanation:

To find the empirical formula we need to determine first the percentage of each atom in the molecule. Then, we need to find the moles and, as empirical formula is the simplest whole-number ratio of atoms we can solve the empirical formula:

%C:

0.33gC / 2.12g * 100 = 15.6%

%S:

1.53g S / 1.82g * 100 = 84.1%

In a basis of 100, the moles of each atom are:

C:

15.6g C * (1mol / 12.01g) = 1.30 moles

S:

84.1g S * (1mol / 32.065g) = 2.62 moles

The ratio of Sulphur-Carbon is:

2.62mol / 1.30mol = 2

That means empirical formula is:

CS₂