Mystery Element Identification

Question

A 2.0g sample of SX6 (g) has a volume of 329.5 cm3 at 1.00 atm and 20oC. Identify the element ‘X’. Name the compound.

Coul you please show how to do it as well, not just the answer

Much thanks in advance

Answer 1

number of moles

use pV=nRT

n=pV/RT  

I use MKS units  p=101325 Pa  v= 3.295*10-4m^3  T=20+273=293K

n= 101325*3.295*10^-4/(8.314*293)=0.0317mol...

so 1 mole has a mass 2/0.0137=146G

So mass molar of SX6 =146=32+6X

6X=146-32=114

mass of X=114/6=19

This is fluorine

formula SF6

Answer 2

I am not entirely sure of the method as I have only done GCSEs but i am fairly sure that the element is oxygen.