Determine the empirical and molecular formulas of a compound that contains 56.36% o and 43.64% p and has a molar mass of 284 g/mo

Step 1; calculate the number of moles of each element (moles = % composition / molar mass)

that is P = 43.64 / 30.974 = 1.41 moles

O = 56.36 / 15.999 = 3.52 moles

then find the mole ratio by diving both mole with smallest number of mole

that is P = 1.41/1.41 = 1 mole

O = 3.52 / 1.41 = 2.5 moles

multiply by both mole ratio by 2 to remove the decimal

p = 1 x2 = 2 moles

O = 2.5 x2 = 5 moles

therefore the empirical formula = P2O5

molecular formula is calculated as follows

(P2O5) n = 284 g/mol

{ (30.974 x2) + (15.999x5) }n = 284 g/mol

141.943n = 284 g/mol

divide both side by 141.943

n=2

therefore the molecular formula = (P2O5) 2 = P4O10