Question

Calculate the percentage of each element in acetic acid, hc2h3o2, and glucose, c6h12o6.

Answer 1

Acetic acid, HC2H3O2

First, calculate for the molar mass of acetic acid as shown below.
    M = 1 + 2(12) + 3(1) + 2(16) = 60 g

Then, calculating for the percentages of each element.
 Hydrogen:
    P1 = ((4)(1)/60)(100%) = 6.67%

 Carbon:
   P2 = ((2)(12)/60)(100%) = 40%

Oxygen
  P3 =((2)(16) / 60)(100%) = 53.33%

Glucose, C6H12O6

The molar mass of glucose is as calculated below,
   6(12) + 12(1) + 6(16) = 180

The percentages of the elements are as follow,
  Hydrogen:
   P1 = (12/180)(100%) = 6.67%

Carbon:
  P2 = ((6)(12) / 180)(100%) = 40%

Oxygen:
  P3 = ((6)(16) / 180)(100%) = 53.33%

b. Since the empirical formula of the given substances are just the same and can be written as CH2O then, the percentages of each element composing them will just be equal.