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? a. no2, no8, no10
b. no4, no10, no5
c. n2o, n2o4, n2o5
d. no, no2, no4

The possible formula in Dalton's time (had never heard of a mole)

a. NO₂, NO₈, NO₁₀

c. N₂O, N₂O₄, N₂O₅

Dalton's law of multiple comparisons states that if elements are forming two or more kinds of compounds, if the mass of one of the elements is known to be the same / fixed, then the mass of the second element in the two compounds will have a ratio as a simple integer.

The available samples show the ratio of masses of elements N and O as follows:

To simplify numbers into simple integers, we multiply all the comparisons above by multiplying 7, so we get:

Compound A: 7: 4

Compound B: 7:16

Compound C: 7:20

From the results of this comparison shows that for the same number of N, the ratio of element O is 4:16:20 = 1: 4: 5 (fulfills Dalton's theory)

So according to Dalton (because there is no concept of the mole) then there is a possibility that the compound is:

a. NO₂, NO₈, NO₁₀

c. N₂O, N₂O₄, N₂O₅

But if we use the mole concept which shows the empirical formula of the compounds, the mole ratio of each compound is:

5.6 / 14: 3.2: 16 = 0.4: 0.2 = 2: 1

3.5 / 14: 8/16 = 0.25: 0.5 = 1: 2 = 2: 4

1.4 / 14: 4/16 = 0.1: 0.25 = 2: 5

So if we use the mole concept, then the appropriate compound is c. N₂O, N₂O₄, N₂O₅

A sample of H₂SO₄

link

The amount of hydrogen, carbon, nitrogen, and oxygen in caffeine

link

determine the number of each atom present in the compound formula

link

Keywords: Dalton, the law of multiple comparisons

personal, she chose to do it.