how do i solve this chemistry problem?

Question

an oxide of nitrogen is 26% nitrogen by mass. the molar mass of the oxide is approximately 105g/mol. what is the formula of the compound?

will someone please explain/show me how to do this one? i've been stuck on it for a while. thank you very much

Answer 1

In 100 g we have 26 g of N ( 26 / 14 = 1.86 moles ) and 74

g of O ( 74 / 16 = 4.62 moles O)

to get the empirical formula we divide for the smallest number:

4.62 / 1.86 = 2.5

N O(2.5 ) >> N2O5

Answer 2

The steps are the same at EVERY compound, so :lets suppose it has n atoms of N in a molecule, and m atoms of oxigen. Your compound would be NnOm. Molecular mass would mean

M=n*(atomic mass of nitrogen)+m*(atomic mass of oxigen)=
n*14+m*16 g/mol

this means one mol would be 14*n+16*m grams, but from that 26% is the nitrogen, so

14*n+16*m............................100%

14*n.............................26%

26*(14*n+16*m)=100*14*n
but we know that the molecular mass
14*n+16*m=105(approximately means that the atomic masses are always used as rounded numbers... specifically it would be a bit more or less because of the mass of electrons in an atom)
26*105=1400*n
n=1.95

14*1.95+16*m=105 -> m=4.85

n=1.95, m=4.85
dont get afraid of these numbers, obviously we cannot use them to give the molecule , but the result shows that APPROXIMATELY
n:m is 2:5
so you were looking for N2O5 dinitrogen-pentoxid

Answer 3

The N is 26% so that means the O is 100-26 = 74%.

Let us assume 100 grams of the substance is present.

This means 26 grams is N and 74 grams is O

Divide each mass by the atomic weight. Do not round off very far.

N is 26 / 14.007 which equals 1.856
O is 74 / 16.000 which equals 4.625

Divide each answer by the smallest value

N = 1.856 / 1.856 which is 1
O = 4.625 / 1.856 which is 2.5

N2O5 is your answer. You may calculate its molar mass

Answer 4

To try something different....

1 mole of ideal gas = 22.4L
26% = 0.224 x 26 = 5.8
74% = 0.224 x 74 = 16.8
16.8 ÷ 5.8 = 2.9. Ratio = 1:3
Formula = NO3

Check: NO3 = 14 + 48 = 62 ....
...N = 14/62 = 0.226 = 22.6%
...O3 = 48/62 = 0.774 = 77.4%
Total - 100%

Answer 5

0.26 x 105 = 27.30

This corresponds to two atoms of N per molecule.

Mass of O = 105-28 = 86 (5 atoms of Oxygen)

Compound is N2O5, Dinitrogen Pentoxide.