petrolum etherpfund seriesph meterphamaceutical chemistryphase diagramphase integalphase rulephase spacephase speedphase transitionphase velocityphenol coefficientphenol redphenolphthaleinphenyl benzoyl carbinolphenyl ketonephononphosphatasephosphate rockphosphoranephosphorescencephosphorescentphosphoritephosphorusphosphoryl groupphoto excitationphotocellphotochemistryphotoconductive cellphotodecompositionphotodissociationphotoelectric cellphotoelectric effectphotoelectricityphotographic chemistryphotographic fixingphotoionizationphotolysisphotometerphotometryphotonphoton counterphotopolymerphototropsimphototropyphysical changephysical chemistryphysical constantphysical statephytochemistry