Calculate the empirical formula of vitamin C where the compound is 40.9% C, 54.4% O and 4.58% H by mass.

Question

| General Chemistry 2

Accepted Answer

The empirical formula of vitamin C is C_XO_YH_Z⇒ M_CxOyHz = X M_C + Y M_O + Z M_H = 12.0 X + 16.0 Y + 1.01 Z

%C = 12.0 X / M_CxOyHz = 0.409
%O = 16.0 Y / M_CxOyHz = 0.544
%H = 1.01 Z / M_CxOyHz = 0.0458

If X = 1, M_CxOyHz = 29.3 g.mol^-1 and Y = 1 and Z = 1.33.

X, Y and Z must be the smallest whole number possible, so X=3, Y=3 and Z=4

The empirical formula of vitamin C is C₃O₃H₄

Percent Composition by Mass - 2 | Chemical Calculations