Ascorbic acid (vitamin C) contains 40.92% carbon, 4.58% hydrogen and 54.5% of oxygen by mass. What is the empirical formula of ascorbic acid?

Explanation

The empirical formula is the ratio between the number of atoms of different elements which is present in the molecule of the given compound. Empirical formulas usually give the proportion of the elements present in the molecule of the given compound but not the actual number of the atoms or how the atoms are arranged. Complete step by step answer: If the mass of the compound is given then the empirical formula is calculated by changing the mass of every element to moles and then by dividing every mole value by the lowest value of mole computed and then the value of mole is rounded off to the closest whole number. Given in the question: 100% of vitamin C contains 40.92% carbon by mass, 4.58% hydrogen, and 54.50% oxygen Or we can say that 100 g of vitamin C contains 40.92 g carbon by mass, 4.58 g hydrogen, and 54.50 g oxygen. The atomic mass of carbon = 12 g/mol The atomic mass of hydrogen = 1 g/mol The atomic mass of oxygen = 16 g/mol The number of moles is calculated by the ratio of the given mass to the molar mass. Number of moles of carbon = 40.92\12 = 3.4 mole Number of moles of hydrogen = 4.58\1 = 4.58 mole Number of moles of oxygen = 54.50\16= 3.40 mole The molar ratio of carbon, hydrogen, and oxygen is: C:H:O 3.4 : 4.58 : 3.4 = 3:4:3 C3H4O3 So, the correct answer is "Option A". Note: If the molecular formula of a compound is given then to calculate the empirical formula from the molecular formula we have to divide all the subscripts in the empirical formula by the simplest whole number. The molecular formula is the actual whole number ratio of the elements present in the molecule of the compound.