Uranium-235 is an important nuclear fuel. However, the ^235Uisotope is only a very small amount of naturally occurring uranium. Therefore, taking advantage of gas diffusion rates and molecular masses, naturaly occurring uranium(IV) oxide is converted to uranium(IV) fluoride and this in turn is converted to urnaium (VI) fluoride in a reaction with fluorine gas. The uranium (VI) fluoride is a gas and the different masses of the two uranium(VI) fluoride isotopes can be separated. Using the date below, determine the lattice energy,
delta H lattice energy of the uranium(IV) fluoride that is formed in the reactions described above.
1. U(s) + O2(g) 6UO2(s) DeltaH= !1084.9 kj/mol
2. UO2(s) + 4HF(g) 6 UF4(s) + 2H2O(g) DeltaH= !228.5kJ/mol
3. 1/2H2(g) + 1/2 F2(g) 6HF(g) DeltaH= !271.1 kJ/mol
4. H2(g) + 1/2 F2(g) 6 H2O(g) DeltaH= !241.8 kJ/mol
5. U(s) 6U(g) DeltaH= 527.2 kJ/mol
6. U(g) 6 U^4+ (g) = 4 e IE=11800 kJ/mol
7. F2(g) 6 2F(g) BE= 159 kJ/mol
8. F(g) + e 6 F^! (g) EA= !328 kJ/mol
9. U^4+ (s) + 4F^! (g) UF4 (s) LE= ?