Question

Samples of three different compounds were analyzed and the masses of each element were determined.

Compound Mass N
(g) Mass O
(g)
A 5.6 3.2
B 3.5 8.0
C 1.4 4.0
If you were John Dalton and had never heard of a mole, which of the following would you think were possible sets of formulas for the compounds A, B, and C, respectively?
Check all that apply.
Check all that apply.
NO2, NO8, NO10
N2O, N2O4, N2O5
NO, NO2, NO4
NO4, NO10, NO5

Answer 1

First, you have to convert mass to moles by making use of molecular weights [N = 14 g/mol and O = 16 g/mol)

A.
5.6/14 = 0.4 mol N
3.2/16 = 0.2 mol O
mol ratio = 2 mol N/1 mol O => N2O

B.
3.5/14 = 0.25 mol N
8.0/16 = 0.5 mol O
mol ratio = 1 mol N/2 mol O => NO2

C.
1.4/14 = 0.1 mol N
4.0/16 = 0.25 mol O
mol ratio = 2 mol N/5 mol O => N2O5