The % yield of Hf is 91. 8%
calculation
% yield = actual mass/ theoretical mass x100
actual mass = 2.85 Kg
calculate the theoretical mass
by first write the equation for reaction
CaF2 +H2SO4 → 2HF + CaSO4
find the moles of CaF2 used
moles = mass/molar mass
mass = 6.05Kg = 6.05 x1000 =6050 Kg
molar mass of CaF2 = 40 + (19 x2) = 78 g/mol
moles= 6050/ 78 = 77.6 moles
by use of mole ratio between CaF2 to HF which is 1:2 the moles of HF is therefore = 77.6 x2 =155.2 moles of Hf
find the theoretical mass of HF = moles x molar mass ( 1 +19=20g/mol)
= 155.2 moles x 20 g/mol = 3104 grams = 3104 /1000 = 3.104 Kg
The % yield is therefore = 2.85 Kg/ 3.104 Kg x100 = 91.8%
