Answer:
Molecular formula = C6H8O6
The molar mass of vitamin C = 176.14 g/mol
Explanation:
Step 1: Data given
Mass of vitamin C = 7.75 grams
Mass of CO2 = 11.62 grams
Mass of H2O = 3.17 grams
Molar mass of CO2 = 44.01 g/mol
Molar mass of H2O = 18.02 g/mol
Molar mass C = 12.01 g/mol
Molar mass H = 1.01 g/mol
Molar mass O = 16.0 g/mol
Step 2: Calculate moles CO2
Moles CO2 = 11.62 grams /44.01 g/mol
Moles CO2 = 0.264 moles
Step 3: Calculate moles C
For 1 mol CO2 we have 1 mol C
For 0.264 moles CO2 we have 0.264 moles
Step 4: Calculate mass C
Mass C = 0.264 moles * 12.01 g/mol
Mass C = 3.17 grams
Step 5: Calculate moles H2O
Moles H2O = 3.17 grams / 18.02 g/mol
Moles H2O = 0.176 moles
Step 6: Calculate moles H
For 1 mol H2O we have 2 moles H
For 0.176 moles H2O we have 2*0.176 = 0.352 moles
Step 6: Calculate mass H
Mass H = 0.352 moles * 1.01 g/mol
Mass H = 0.356 grams
Step 7: Calculate mass O
Mass O = 7.75 grams - 3.17 - 0.356
Mass O = 4.224 grams
Step 8: Calculate moles O
Mass O = 4.224 grams / 16.0 g/mol
Mass O = 0.264 moles
Step 9: Calculate mol ratio
We divide by the smallest amount of moles
C: 0.264 moles / 0.264 moles = 1
H: 0.352 moles / 0.264 moles = 1.33
O: 0.264 moles / 0.264 moles = 1
This means for each C atom we have 1.33 H atoms and 1 O atom
OR
For every 3 C atoms we have 4 H atoms and 3 O atoms
The empirical formula is C3H4O3
Step 10: Calculate the molecular formula
The molecular mass of the empirical formula is 88.07
Since the molar mass of vitamin C is between 150 and 200 g/mol
We have to multiply the empirical formula by 2
Molecular formula = 2*(C3H4O3) = C6H8O6
The molar mass of vitamin C = 176.14 g/mol
