Find number of moles of phosphorusmolar mass of phosphorus is 30.97g/moldivide mass by molar mass to get the moles of phosphorus please that your molar mass mast be multiplied by 4 because you have four phosphorus atoms. 30.97*4= 123.88 g/moln= m/M = 62.0g/123.88g/mol= 0.50 molesTheoretically, there are 6 times the number of moles in fluorine than there are in phosphorus because of the ratio 1:6 but fluorine is diatomic gas so we multiply the number of moles by 12 instead of 6. 6 from the ratio times from fluorine being diatomic gas.So 0.5*12=6 moles of fluorine. we multiply that by the molar mass of fluorine multiplied by 12 because we 12fluorine atoms.So, 6= m/228g/mol so to find mass of fluorine we multiply moles times molar mass it gives us 1368g.