Consider 4 g N2O5, in a test tube. [Given: Ar(N) = 14, Ar(O) = 16] What is the percentage oxygen in N2O5? (Give your answer in 4 significant figures)​

74.08%

Explanation:

We'll begin by calculating the mass of

Oxygen in 4 g of N₂O₅. This can be obtained as follow:

Molar mass of N₂O₅ = (14×2) + (16×5)

= 28 + 80

= 108 g/mol

Mass of oxygen in N₂O₅ = 5 × 16 = 80 g

Mass of oxygen in 4 g of N₂O₅

= 80 / 108 × 4

= 2.963 g

Finally, we shall determine the percentage of oxygen in 4 g of N₂O₅. This can be obtained as follow:

Mass of oxygen = 2.963 g

Mass of N₂O₅ = 4 g

Percentage of oxygen =?

Percentage of oxygen = mass of oxygen / mass of N₂O₅ × 100

Percentage of oxygen = 2.963 / 4 × 100

Percentage of oxygen = 74.08%

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)

it's c (engineer's do their work with mechanical stuff not on any living being)