Answer:
C4H8O6 is the molecular formula
The molar mass is 152 g/mol
Explanation:
Step 1: Data given
Mass % C = 31.57%
Mass % H = 5.30 %
Mass % O = 100 - 31.57 - 5.30 = 63.13 %
The freezing point = –5.30°C
Mass of the compound = 10.8 grams
Mass of water = 25.0 grams
compound is a nonelectrolyte.
Step 2: Calculate moles of elements
moles C = 31.57 grams/ 12.01 g/mol = 2.629 moles
moles H = 5.30 grams/ 1.01 g/mol = 5.25 moles
moles O = 63.13 grams / 16.0 g/mol = 3.95 moles
Step 3: Calculate the mol ratio
We divide by the smallest number
C: 2.629 moles / 2.629 moles = 1
H: 5.25 moles / 2.629 moles = 2
O: 3.95 moles / 2.629 moles = 1.5
The empirical formula is C2H4O3
The molecular mass of this is 76.06 g/mol
Step 4: Calculate moles solute
5.30 = m * 1.86
m = 2.85 = moles solute / 0.025 Kg
moles solute = 2.85 * 0.025 = 0.07125 moles
Step 5: Calculate molar mass
molar mass = 10.8 grams / 0.07125 moles = 152 g/mol
Step 6: Calculate molecular formula
152/76.06 ≈ 2
We have to multiply thr empirical formula by 2
2*(C2H4O3) = C4H8O6
C4H8O6 is the molecular formula
