Answer:
THE MOLECULAR FORMULA FOR THE LACTIC ACID IS C3H6O3
Explanation:
Lactic acid is composed of carbon, hydrogen and oxygen.
It has molar mass of 90 g/mol
Constituents composition:
Carbon = 40.0 %
Hydrogen = 6.71 %
Oxygen = 100 - (40 + 6.71) = 53.29 %
First we calculate the empirical formula
1. Divide the percentage composition by its atomic mass of each element.
(C = 12 , H = 1, O = 16)
Carbon = 40 / 12= 3.333
Hydrogen = 6.71/1 = 6.71
Oxygen = 53.29 / 16 = 3.33
2. Divide each value of the element by the smallest of them.
carbon = 3.333/ 3.33 = 1
Hydrogen = 6.71 / 3.33 = 2.015
Oxygen = 3.33 / 3.33 = 1
3. The empirical formula is therefore
C H2 O
4. Calculate the molecular formula
(CH2O)n = Molar mass
( 12 + 1 *2 + 16)n = 90
(30)n = 90
n = 90 / 30
n = 3
The molecular formula is written as
(CH2O) 3
= C3H6O3
Hence, the molecular formula for the lactic acid is C3H6O3.
