A student has stored 250 mL of helium gas over water on a cool day when the temperature in the room reads 20.5°C. If the barometric pressure in the room is
768 mm Hg, what is the pressure of the helium gas in its container?

Ibelieve y y even though i've only taken chemistry for one year

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