pasteurizationpatternpattern recognitationpauli exclusion principlepbpdpeakpeak widthpearl polymerizationpenetrabilitypenetrationpentagonpentagonalpentagonal pyramidpentoxidepeptidepeptide bondpeptide linkagepeptizationpercipitateperfect gasperiodperiodic tableperiodicityperkine condensationpermanent hardnesspermanent magnetpermeabilitypermeable membrancepermeationpermittivitypermselectivepermselectivitypermutationperoxideperoxy acidperoxymonosulfuric acidperpetual motion machineperspective formulaperturbationperturbation theorypesticidepestlepetri dishpetrochemicalspetrochemistrypetrolatumpetroleumpetroleum productspetrolum chemicals