Question

The molar mass of a substance is 92.010g. The substance is 30.4% nitrogen and 69.9% oxygen. What is the empirical formula and the molecular formula of the substance

Answer 1

Answer:

Empirical formula = NO₂

Molecular formula = N₂O₄

Explanation:

Percentage mass of Nitrogen = 30.4 %

Percentage mass of Oxygen = 60.9 %

Mole ratio of the elements:

Nitrogen = 30.4/14 = 2.17

Oxygen = 69.9/16 = 4.37

Dividing by the smallest ratio to obtain a simple ratio

Nitrogen: 2.17/2.17 = 1

Oxygen; 4.37/2.17 = 2

Therefore, the simplest mole ratio is 1:2

Empirical formula = NO₂

Molecular formula = n(empirical formula), therefore, molecular mass = n *(empirical mass)

92.010 = n(14 + 32)

92.010 = 46n

n = 92.010/46

n = 2

Therefore, molecular formula = 2(NO₂)

Molecular formula = N₂O₄