Question

A 283.3-g sample of X2(g) has a volume of 30 L at 3.2 atm and 27 'C. What is element X?

Answer 1

we find the number of moles with the formula

pV=nRT

27C=300k

3.2*30=n*0.082*300

n=96/24.6=3.9 moles

we have the mass ant the number of moles so we can calculate the molar mass

283.3/3.9=72.64g/moles

that means X's mass is 72.64/2=36.3 so the element is Kr(Kriptonium)