A compound containing nitrogen and oxygen is decomposed in the laboratory and produces 1.78 g of nitrogen and 4.05 g of oxygen, calculate empirical formula

First step

calculate the moles of each element

moles = mass/molar mass

N = 1.78g / 14 g / mol = 0.127 moles

O = 4.05g/16 g/mol = 0.253 moles

then find the mole ratio by dividing with the smallest mole number in each element

that is N = 0.127/0.127 = 1mole

O = 0.253/0.127 = 2moles

therefore the empirical formula is NO2