A compound contains 53% Al and 47% O by mass. What
is the empirical formula of this compound?

Ch4 and ph3 are both covalent since they are composed both of non-metals.    ch4 is non- polar because of  london forces and has a geometry of tetrahedral  ph3 , on the other hand, is umbrella shaped polar and has dipole-dipole intermolecular force (imf) . since ph3 is polar, it has a stronger imf   

Your question is not clear but if you can explain yourself i would be glad to .  just trying to : ))

50? i have no !

Ibelieve it's dna hope this out at least