The molality is defined as amount of solute divided by mass of solvent in kilogrammes. Hence first convert the mass of solvent to kilogrammes and the divide the given amount of solute in moles by this mass of solvent in kilogrammes. This gives us the molality of the solution
Moles XeF6 = 10.0g/ 245.28 g/ mol=0.0408 The ratio between F2 and XeF6 is 3:1 Moles F2 required = 3 x 0.0408=0.122 Mass F2 = 0.122 mol x 37.9968 g/ mol=4.64g
