11. Tungsten can also be obtained by reacting tungsten
fluoride with hydrogen. The equation for this reaction is
WF + 3H₂ à W + 6HF
6
(i) In an experiment, a chemist used 59.6 g of tungsten
fluoride. What is the maximum mass of tungsten he
could obtain from 59.6 g of tungsten fluoride?
Relative formula mass of tungsten fluoride = 298 (2)
maximum mass =
g
(ii) Starting with a different mass of tungsten fluoride, he
calculates that the mass of tungsten formed should be
52.0 g. In his experiment he actually obtains 47.5 g of
tungsten. What is the percentage yield of tungsten in
this experiment? (2)
percentage yield
%