Question

a compound with a molar mass of 92g/mol contains 0.3955g of nitrogen and 0.904g of oxygen. Determine the empirical and molecular formula

Answer 1

Empirical: NO2. Molecular: N2O4

Step-by-step explanation:

In order to determine the empirical formula, we divide each element's mass by their respective molar mass:

N: 0.3955g/14.01 g/mol = 0.02823 mol

O: 0.904g/16.00 g/mol = 0.0565 mol

Next, we take the smallest value and multiply it till it is close enough to an integer:

0.02823 x 40 = 1.12 Close enough to 1.

0.0565 x 40 = 2.26. Close enough to 2.

Therefore, the Empirical Formula is: NO2

Next, we determine how much the Empirical formula weighs and see if it matches 92g/mol:

14.01 g/mol + 2(16.00 g/mol) = 46.01 g/mol

We can assume this is roughly half of 92 g/mol so we can multiply each subscript by 2 to match the weight.

Therefore, the Molecular formula is N2O4

Hope this helped!