Volcanic molten lava pours out and re-hardens back into the rock again. Chemical change or physical change?

Sorry i dont understand the question can you rephase it?

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