A sample of an organic compound with mass of 0.816g was completely burn in oxygen and found to produce 1.556g of co2 and 0.955g of H2O only .calculate the empirical formula if the vapour density is 23?
CxHy + O2 ==> CO2 + H2O (not balanced)
mols CO2 = grams CO2/molar mass = 1.556/44 = about 0.035 = mols C,
mols H2O = 0.955/18 = about 0.053 and mols H = 0.106; i.e., 2*0.053.
mols C = 0.035
mols H = 0.106
Find the ratio of C:H with the smallest number being no less than 1. To do that divide both numbers by the smaller of the two.
0.035/0.035 = 1
0.106/0.035 = 3.03 which rounds to 3.0 so the empirical formula is
C1H3 or CH3. This is the empirical formula. You must have meant to calculate the molecular formula.
vapor density = molar mass compound/molar mass H2 or
23 = molar mass compound/2.016 so molar mass compound = 2.016 x 23 = about 46.3. Thus you know that the molecular formula is a whole multiple of CH3 or 15 so 46.3/15 = about 3.08 which rounds to 3.00 to a whole number so the molecular formula must be (CH3)3 or C3H9.
how did we get 44 to divide 11.556
To determine the empirical formula of the organic compound, we need to calculate the moles of carbon and hydrogen in the given quantities of CO2 and H2O.
1. Calculate the moles of CO2:
Mass of CO2 = 1.556 g
Molar mass of CO2 = 44.01 g/mol
Moles of CO2 = (Mass of CO2) / (Molar mass of CO2)
Moles of CO2 = 1.556 g / 44.01 g/mol
2. Calculate the moles of H2O:
Mass of H2O = 0.955 g
Molar mass of H2O = 18.02 g/mol
Moles of H2O = (Mass of H2O) / (Molar mass of H2O)
Moles of H2O = 0.955 g / 18.02 g/mol
3. Calculate the moles of carbon:
Since 1 molecule of CO2 contains 1 carbon atom, the moles of carbon is equal to the moles of CO2.
4. Calculate the moles of hydrogen:
Since 1 molecule of H2O contains 2 hydrogen atoms, the moles of hydrogen is twice the moles of H2O.
5. Calculate the empirical formula:
Divide the moles of carbon and hydrogen by their smallest value to get the empirical formula ratio.
Example:
If the moles of carbon = 1.25 and the moles of hydrogen = 2.50,
Dividing by the smallest value (1.25), we get approximately:
C = 1 and H = 2
Therefore, the empirical formula is CH2.
To determine the empirical formula of the organic compound, we need to analyze the data provided and calculate the molar ratios of the elements present.
1. Calculate the moles of CO2 produced:
The molar mass of CO2 is 44 g/mol.
Moles of CO2 = Mass of CO2 / Molar mass of CO2
Moles of CO2 = 1.556 g / 44 g/mol
2. Calculate the moles of H2O produced:
The molar mass of H2O is 18 g/mol.
Moles of H2O = Mass of H2O / Molar mass of H2O
Moles of H2O = 0.955 g / 18 g/mol
3. Determine the moles of carbon and hydrogen:
Since the organic compound completely burns to produce CO2 and H2O, the carbon in the compound will be found in CO2, and the hydrogen will be found in H2O.
Moles of carbon = Moles of CO2
Moles of hydrogen = Moles of H2O
4. Calculate the moles of organic compound:
Moles of organic compound = Moles of carbon + Moles of hydrogen
5. Calculate the molecular weight of the organic compound:
The molecular weight of a compound is the sum of the atomic masses of its elements.
Molecular weight = Mass of organic compound / Moles of organic compound
Molecular weight = 0.816 g / (Moles of carbon + Moles of hydrogen)
6. Calculate the empirical formula:
Empirical formula = Elements in the compound with their respective ratios.
Now, as the molecular weight is given by the vapour density, we can substitute the value of molecular weight with the vapour density (VD).
VD = Molecular weight
VD = 23 g/mol
Empirical formula = Elements in the compound with their respective ratios.
For example, if the ratio of carbon to hydrogen in the organic compound is 1:2, the empirical formula would be CH2.
By following these steps and plugging in the given values, you should be able to calculate the empirical formula of the organic compound.