Question

A compound is composed of 24.27% carbon, 4.08% hydrogen, and 71.65% chlorine. The compound has a molar mass of 98.96 g/mol.

A. What is the empirical formula of the compound?
B. What is the molecular formula of the compound?

Answer 1

A)

we have mass of each elements as:

C: 24.27 g

H: 4.08 g

Cl: 71.65 g

Divide by molar mass to get number of moles of each:

C: 24.27/12.01 = 2.0208

H: 4.08/1.008 = 4.0476

Cl: 71.65/35.45 = 2.0212

Divide by smallest to get simplest whole number ratio:

C: 2.0208/2.0208 = 1

H: 4.0476/2.0208 = 2

Cl: 2.0212/2.0208 = 1

  

So empirical formula is:CH2Cl

Answer: CH2Cl

B)

Molar mass of CH2Cl,

MM = 1*MM(C) + 2*MM(H) + 1*MM(Cl)

= 1*12.01 + 2*1.008 + 1*35.45

= 49.476 g/mol

Now we have:

Molar mass = 98.96 g/mol

Empirical formula mass = 49.476 g/mol

Multiplying factor = molar mass / empirical formula mass

= 98.96/49.476

= 2

So molecular formula is:C2H4Cl2

Answer: C2H4Cl2