I. The compound
uranium hexafluoride, known as "
hex" amongst nuclear engineering types can be prepared from elemental
uranium (238 g/mol) and
chlorine trifluoride via the reaction:
2 ClF
3(g) + U(s)
UF
6(s) + Cl
2(g)
(1) Given that one begins with 15.90
L of ClF
3 (at
6.80 atm and 298 K) and 0.450
kg of
uranium metal, determine the number of
equivalents of each reactant and indicate which species is the limiting reactant.
Eq (ClF
3):
2.21 (ANSWER KEY)
Eq (U):
1.89 (ANSWER KEY)
Limiting reactant:
U (ANSWER KEY)
For this one this is what I did:
PV = nRTPV/RT = n
(6.80 atm)(15.90 L)/(0.0821 L*atm/mol*K)(298 K) = n
108.12/24.5 = n
4.413 mol ClF
3= n (INCORRECT)
They divided this answer by 2! Why??
You can't do 4.413 mol ClF
3 x 1 mol ClF
3/2 mol ClF
3 = 2.2065. Can you??
From there, would I go about solving Eq U like this?
2.2065 mol ClF
3 x 1 mol U/2 mol ClF
3 = 1.10325.
But this is wrong too, since the answer is supposed to be 1.89.
(2) Assuming the same starting amounts as in part (1), what is the actual yield of
UF6(s) in kilograms if the percent yield of the process is only 74%?