Answer
The compound with the greatest molar mass is silicon tetrabromide
Explanation
Using the atomic masses of C, F, Si, P, Cl, and Br from the Periodic table, the molar masses of the compounds are calculated below
C = 12, F = 19, Si = 28, P = 31, Cl = 35.5 Br = 80
Molar mass of silicon tetrabromide, SiBr₄ = 28 + (4 x 80) = 348 g/mol
Molar mass of silicon tetrafluoride, SiF₄ = 28 + (4 x 19) = 104 g/mol
Molar mass of carbon tetrafluoride, CF₄ = 12 + (4 x 19) = 88 g/mol
Molar mass of phosphorus trichloride, PCl₃ = 31 + (3 x 35.5) = 137.5 g/mol
Therefore, the compound with the greatest molar mass is silicon tetrabromide
