When 0.422g of phosphorus is burned, 0.967g of a white oxide is obtained.

a. Determine the empirical formula of the oxide

b. write a balanced equation for the reaction of phosphorus and molecular oxygen on the basis of this empirical formula

Moles = mass / molar mass

moles P = 0.422 g / 30.97 g/mol = 0.01363 mol

moles O = (0.967 g - 0.422g) / 16.00 g/mol = 0.03406 moles

So ratio moles P : moles O

= 0.01363 mol : 0.03406 mol

Divide each number in the ratio by the smallest number

(0.01363 / 0.01363) : (0.03406 / 0.01363)

= 1 : 2.5

The empirical formula needs to be the smallest whole number ratio of atoms in the molecules. Since you have a non-whole number, multiply the ratio by the smallest number needed to make both number whole numbers. In this case x 2

2 x (1 : 2.5)

= 2 : 5