Answer:
Molecular formula for the organic compound is: C₉H₁₈O₃
Explanation:
We determine the combustion reaction:
CₓHₓOₓ + O₂ → CO₂ + H₂O
We don't know the subscrip of the organic compound, that's why we put x.
Notice we have C in the compound and in CO₂. Let's find out the mass of C. 1 mol of CO₂ contains 1 mol of C
Then (7.950 g /44g/mol) of CO₂ may contain ?
(7.950 g /44g/mol) represents the moles of dioxide → 0.181 moles of C
These moles came from the mass of the organic compound, the 3.498 g.
So now, we can know the subscript for C.
If 3.498 g of the compound contain 0.181 moles of C
174.27 g of the compound may contain (174.27 . 0.181)/ 3.498 = 9
Let's do the same for the H.
1 mol of water contain 2 moles of H
(3.255 g /18 g/mol) of water, may contain ?
3.255 g /18 g/mol = 0.181 moles . 2 = 0.362 moles of H
These moles came from the mass of the organic compound, the 3.498 g.
Let's find out the subscript for H
If 3.498 g of the compound contain 0.362 moles of H
174.27 g of the compound may contain (174.27 . 0.362)/ 3.498 = 18
Organic compound is C₉H₁₈Oₓ. If the molar mass is 174.27 g we can easily determine the moles of O
12 g/mol . 9 + 1 g/mol . 18 + 16 g/mol . X = 174.27 g/mol
(174.27 g/mol - 12 g/mol . 9 - 1 g/mol . 18 ) / 16 = 3
Molecular formula for the organic compound is: C₉H₁₈O₃. Therefore the complete combustion reaction is:
C₉H₁₈O₃ + 12O₂ → 9CO₂ + 9H₂O
