What is the molecular formula of this compound ?

Question

Elemental ananalysis of a compound results in the following data

65.45 % C

5.49 % H

29.06 % O


4.13 g of the compound fills a 183.0 ml bottle with a pressure of 2508.6 mm Hg at a temperature of 21.3oC.

Answer 1

1. Get the empirical formula of the compound,
Assume 100g of the compound and get their number of moles.

C: 65.45g/ 12g/mol = 5.454 mol
H: 5.49g/ 1g/mol = 5.49 mol
O: 29.06g/ 16g/mol = 1.816 mol

Divide results by the smallest number of moles. You'll get: 3C, 3H, and 1O. Your empirical formula then is C3H3O.

2. Determine the molar mass of the compound using this equation: MM = gRT/PV.
MM = (4.13g * 62.3637 L·mmHg /K·mol * 294.3K) / (2508.6 mmHg * 0.183L)
MM = 165.11 g/mol

3. Determine molecular formula by identifying multiplier of the empirical formula C3H3O to get MM of 165.11g/mol.

(3*12)x + (3*1)x + (1*16)x = 165.11
36x + 3x + 16x = 165.11
55x = 165.11
x = 3

Hence, your molecular formula is C9H9O3.

Answer 2

C3H30 using the empirical formula

Answer 3

All that I know is that the emperical formula will be C3H30 and this will have a formula mass of 55g