Iodine pentafluoride reacts slowly with glass and violently with water. determine its molecular mass.

               221.90 g.mol⁻¹

                          The mass of contained by a molecule is known as molecular mass. It is the sum of atomic weights of the elements contained by the molecule. In given case Iodine Pentafluoride has a chemical formula,

                                                          IF₅

The atomic weights of each element are as;

                                        Iodine  =  126.90 g.mol⁻¹

                                        Fluorine  =  19.00 g.mol⁻¹

As there are five atoms of Fluorine so, we will multiply the atomic weight of Fluorine by five and that of Iodine by one as there is only one Iodine atom.

Therefore,

         Molecular Mass of IF₅  =  (1 × 126.90 g.mol⁻¹) + (5 × 19.00 g.mol⁻¹)

         Molecular Mass of IF₅  =  (126.90 g.mol⁻¹) + (95.00 g.mol⁻¹)

         Molecular Mass of IF₅  =  221.90 g.mol⁻¹

not clear