Question

Lysine is used as a topical medicinal skin creme. what is the molecular formula of lysine if the empirical formula is c3h7no, and the approximate molar mass is 146 g/mol

Answer 1

Molecular Formula is calculated using following formula,

Molecular Formula  =  n (Empirical Formula)     ----- (1)

Calculating n;

                      n  =  Molecular Weight / Empirical Formula Weight  --- (2)

Empirical formula weight = (12×3) + (1×7) + (14×1) + (16×1)

Empirical formula weight = (36) + (7) + (14) + (16)

Empirical formula weight = 73

Putting values in Eq. 2,

                                n  =  146 / 73

                                n  =  2

Putting Value of n and Empirical Formula in Eq. 1,

Molecular Formula  =  2 × C₃H₇NO

Molecular Formula  =  C₆H₁₄N₂O₂

Result:
           Molecular Formula of Lysine is C₆H₁₄N₂O₂.