Answer
$ CH_2FCF_3 $ : 102.04 g/mol
$ CHClFCF_3 $ : 136.48 g/mol
Work Step by Step
$ CH_2FCF_3 $ : ( 1.008 $\times$ 2 )+ ( 12.01 $\times$ 2 )+ ( 19.00 $\times$ 4 )= 102.04 g/mol
$ CHClFCF_3 $ : ( 35.45 $\times$ 1 )+ ( 1.008 $\times$ 1 )+ ( 12.01 $\times$ 2 )+ ( 19.00 $\times$ 4 )= 136.48 g/mol
