HELP! pH = -log10[H+]. If pH 3.5 what is [H+]?

To find concentration H+ you want to do the inverse log

So 3.5= -log10[x] = 10^-pH
x= 10^-3.5
So [H+]= 3.16*10^-4 M or mol/L

The answer is c. 320 g

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