A8.048 gram sample of an organic compound containing c, h and o is analyzed by combustion analysis and 12.00 grams of co2 and 3.684 grams of h2o are produced.

in a separate experiment, the molar mass is found to be 118.1 g/mol. determine the empirical formula and the molecular formula of the organic compound.

Procedure: The first set of data are use to determine the empirical formula, then the molar mass is used to detemine the molar mass.

1) Quantity of each elements

C: it is only present in CO2.

The ratios of each element in CO2 are: 1 atom C /  2 atom O or, using the atomic masses, 12 g C / 32 g O

Then in 12.00 g of CO2 there are: [12 g C / 44 g CO2] * 12.00 g CO2 = 3.2727 g C

The ratios of each element in H2O are: 2 atom H / 1 atom O or, using the atomic mass, 2 g H / 16 g O

Then in 3.684 g of water there are: [2 g H / 18 g H2O] * 3.684 g H2O = 0.4093 g H

Then the original sample had 8.048 g of Sample - 3.2727 g of C - 0.4093 g of H =  4.366 g of O

2) Now, convert he masses of each element into moles, using the atomic mass of each element

C: 3.2727 g / 12.0 g/mol = 0.2727 mol
H: 4.093 g / 1.0 g/mol = 0.4093 mol
O: 4.366 / 16.0 g/mol =  0.2729 mol

3) Now divide by the smallest number (0.2727) to find the proportion of the elements

C: 0.2727/ 0.2727 = 1.0
H: 0.4093 / 0.2727 = 1.5
O: 0.2729/ 0.2727 = 1.0

Given the the number of mols of H is 1.5 multiply all the numbers by 2 to obtain integer numbers =>

C: 2
H: 3
O: 2

Then, the empirical formula is C2 H3 O2

4) Find the mass of the empirical formula

C: 2 mol * 12.00 g/mol = 24 g
H: 3 mol * 1 g /mol = 3 g
O: 2 mol * 16 g /mol = 32 g

Total mass: 24g + 3g + 32 g = 59 g

5) Finally find the number of times that this mass (59g) is contained in the molar mass (118.1 g) = 118.1 / 59 = 2.00

This is the number for which you have to multiply all the subscripts of the empirical formula to get the molecular formula =>

Then, the molecular formula is C4 H6 O4
 

Hello thereone of the following properties was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version. which property fits this description? answer: atomic mass  was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.