Answer;
= C3H5
Explanation and solution;
1 mole of CO2 contains 44 g, of which 12 g are carbon
Thus, mass of carbon in 9.32 g will be;
(12/44) × 9.32 g = 2.542 g
Mass of Hydrogen in 3.18 g of water;
= (2/18) × 3.18 g = 0.353 g
we then find the number of moles;
Moles of carbon ; 2.542 /12 = 0.2118 moles
Moles of Hydrogen = 0.353 moles
The ratios of C ; H ;
= 1 : 0.353 /0.2118
= 1 : 5/3
= 3: 5
Therefore; the empirical formula of the hydrogen carbon is; C3H5
Mass of CO₂ = 9.32g
Molar mass of CO₂ = 44 g/mol
Mass of H₂O = 3.18 g
Molar mass of H₂O = 18 g/mol
Moles = mass/ molar mass
9.32 g CO₂ x (1 mol CO₂ / 44 g CO₂) = 0.2118 mol CO₂
Every CO₂ molecule has 1 Carbon atom, therefore 0.2118 mol of CO₂ will have 0.2118 moles of C
3.18 g H₂O x (1 mol H₂O / 18 g H₂O) = 0.177 mol H₂O
In every H₂O molecule there are 2 atoms of H therefore 0.177 mol of H₂O will have 2 x 0.177 or 0.354 moles of H
Now the ratio of C : H = 0.2118 : 0.354
To get the whole number we divide both numbers in the ratio by the lowest number.
C : H
= (0.2118/0.2118) : (0.354 / 0.2118)
= 1:1 .67
Since we cannot round, we multiply by 3 to clear the fraction:
C= 1 x 3 =3
H = 1.67 x 3 = 5
Thus the empirical formula is C₃H₅.
