(1) tetrafluoroethylene is produced by the decomposition of difluoromethane, and HCl is also produced. The reaction is 2CHClF 2 →CF 2 =CF 2 +2HCl.

So the answer is: 2 chclf 2→CF 2 = CF 2+2 HCl；; ;

(2) Both tetrafluoroethylene and perfluoropropylene contain C=C bonds, and they undergo addition polymerization to produce perfluoroethylene. The structural formula of perfluoroethylene is as follows

So the answer is: add it together;

(3)PFOA is ammonium perfluorooctanoate, and ammonium octanoate is C 7 H 15 COONH 4, so the chemical formula of PFOA is C 8 F 15 O 2 NH 4, so the answer is c8f 15o2nh4.