How many grams are in 7.62 X 1017 molecules of oxygen?

The number of grams that are in 7.62 x10^17 molecules of oxygen is 4.064 x10^-5 grams

calculation

by use of Avogadro constant find number of moles in 7.62 x10^-17

that is 1 mole = 6.02 x10^23 molecules

? = 7.62 x10 ^17 molecules

cross multiply

(1mole x 7.62 x10^17) / 6.02 x10^ 23 = 1.27 x10^-6 moles

mass = mole x molar mass

molar mass of oxygen molecule = 16 x2=32g/mol

mass = 11.27 x10^-6 moles x 32 g/mol = 4.064 x10^-5 grams