What is the empirical formula of the compound?

[SCGirl]

A 0.4647-g sample of a compound known to contain only carbon, hydrogen, and oxygen was burned in oxygen to yield 0.8635 g of CO2 and 0.1767 g of H2O. What is the empirical formula of the compound? I don't know how to figure this out without percentages of each element.

 

[oceanflavored22]

i can help you! i can help you!

yeah..this is one of those hard stochiometry problems. but nofear; my teacher told us how to do these a month ago, so i can help you :)

kk..you have to think of it like this:
CxHyOz ---> CO2 + H2O

so for CO2, you find the grams of carbon by...
(12.01 g C) / (44.01 g CO2) = 0.27 g (0.8635) = 0.233 g C in CO2
and for H2O, you do the same thing...
(2.02 g H) / (18.02 g H2O) = 0.11 g (.1767) = 0.0194 g H in H2O
and for O, you do...
(0.4647) - (0.233+0.0194) = and get grams of O
and then you can do the rest...i'm getting tiredd lol.

hope that helped!

 

[Blueshift5]

The empirical formula of a compound is the simplest whole-number ratio of atoms present in the compound. In this case, we can determine the empirical formula by first finding the moles of each element present in the compound.

To find the moles of carbon, we divide the mass of CO2 (0.8635 g) by its molar mass (44.01 g/mol). This gives us 0.0196 moles of carbon.

To find the moles of hydrogen, we divide the mass of H2O (0.1767 g) by its molar mass (18.02 g/mol). This gives us 0.0098 moles of hydrogen.

To find the moles of oxygen, we subtract the moles of carbon and hydrogen from the total moles of the compound (0.4647 g / 44.01 g/mol = 0.0106 moles). This gives us 0.0106 - 0.0196 - 0.0098 = -0.0188 moles of oxygen. This negative value means that there is an error in the experimental data, as we cannot have a negative number of moles. Therefore, we can assume that the actual number of moles of oxygen is 0.

Now, we can use the mole ratios to determine the empirical formula. The ratio of carbon to hydrogen is 0.0196 moles : 0.0098 moles, which simplifies to 2:1. This means that the empirical formula contains 2 carbon atoms for every 1 hydrogen atom.

Similarly, the ratio of carbon to oxygen is 0.0196 moles : 0 moles, which simplifies to 1:0. This means that the empirical formula does not contain any oxygen atoms.

Therefore, the empirical formula of the compound is CH2. This compound could be a variety of different molecules, such as ethylene (C2H4) or cyclohexene (C6H12). To determine the specific molecule, we would need additional information, such as the molecular mass or the functional groups present.