Discover a world of knowledge at Westonci.ca, where experts and enthusiasts come together to answer your questions. Connect with a community of experts ready to provide precise solutions to your questions quickly and accurately. Join our platform to connect with experts ready to provide precise answers to your questions in different areas.

When 4.088 grams of a hydrocarbon, CxHy, were burned in a combustion analysis apparatus, 13.82 grams of CO2 and 2.829 grams of H2O were produced.

In a separate experiment, the molecular weight of the compound was found to be 78.11 amu. Determine the empirical formula and the molecular formula of the hydrocarbon.

Sagot :

Answer:

Empirical formula: CH

Molecular formula: C₆H₆

Explanation:

Based on the combustion of a hydrocarbon, the moles of CO₂ = Moles of Carbon in the hydrocarbon and the moles of H₂O = 1/2 moles of hydrogen in the hydrocarbon.

The empirical formula is the simplest whole number of atoms present in a molecule. With the moles of C and H we can find empirical formula:

Moles C -Molar mass CO₂ = 44.01g/mol-:

13.82g * (1mol / 44.01g) = 0.314 moles C

Moles H -Molar mass H₂O = 18.01g/mol-:

2.829g H₂O * (1mol / 18.01g) = 0.157 moles H₂O * (2mol H / 1mol H₂O) = 0.314 moles of H

The ratio of moles H: moles C:

0.314 moles / 0.314 moles = 1

That means empirical formula is:

CH

With the molecular weight and empirical formula we can find the molecular formula:

Molar mass CH = 12.01g/mol+1.01g/mol = 13.02g/mol

As the molecular weight of the molecule is 78.11amu = 78.11g/mol, there are:

78.11g/mol / 13.02g/mol = 6 times the empirical formula in the molecular formula

That means molecular formula is:

C₆H₆