Description
The analysis of an organic compound showed that it contained 0.150 mol C, 0.105 mol H, 0.0300 mol O, and 0.0450 mol N. What would be the subscript on the H in the empirical formula for this compound?
Explanation & Answer
Empirical Formula - A formula that gives the simplest whole-number ratio of atoms in a compound.
the moles of each element are known, a stoichiometric comparison between the elements can be made to determine the empirical formula. This is achieved by dividing through each of the mole quantities by which ever mole quantity is the smallest number of moles. In this example, the smallest mole quantity is either the moles of carbon or moles of Oxygen
0.105/0.0300 = 3.5 C x 2 = 7 C
0.105/0.0300 = 3.5 H x 2 = 7 H
0.0300/0.0300 = 1 O x 2 = 2 O
0.0450/0.0300 = 1.5 N x 2 = 3 N
Multiply by 2 to get whole numbers
Empirical formula is C7 H7 O2 N3
Subscript on H is thus 7
Hope you understand.