CEM-004 –Termodinâmica dos Sólidos – 1° semestre 2015.
Lista de exercícios (6) 05/05/2015
1. In a Ti-H solution ΔHH and ΔGH are given in the following table as a function of XH at 910 K (ΔH
values in calories per gram-atom).
(a) Find ΔGTi at XH=0.4. (b) Find ΔGm at XH=0.4. (c) Find ΔSH at XH=0.4. (d) Find ΔGmxs, ΔGHxs
and ΔSHxs at XH = 0.4.
2. In the preceding problem: (a) Find γH at XH = 0.2. (b) Calculate aH at XH = 0.2. (c) Find the
equilibrium H2 pressure for an alloy of Ti containing 20 at % H (monatomic).
3. Solid Au-Cu alloys are regular in their thermodynamic behavior. ΔHm at 773 K is listed as a
function of composition in the following table.
(a) Find ΔHCu and ΔHAu at XCu = 0.3. (b) Find ΔGm at XCu = 0.30. (c) Calculate the partial pressure of
Cu for an alloy containing 30 at % Cu, 70 at % Au. (d) Calculate the oxygen pressure in equilibrium
with Cu in the alloy in (c) and Cu2O .
4. In the preceding problem suppose that the Cu scale in contact with NiO and a solution forms so that
the activity of Cu2O is 0.4. Calculate the equilibrium oxygen pressure for this case.
5. Sumarize, utilizando como referência parâmetros termodinâmicos, os modelos de solução ideal,
solução diluída, solução regular e solução não regular.
6. Utilize as curvas ao lado e a resposta à questão anterior,
para discutir o efeito da entalpia da mistura sobre a energia
livre da mistura.
7. In a face-centered cubic lattice containing 40 at % A
and 60 at % B in the form of a random solution, calculate
the number of A-A pairs, B-B pairs, and A-B pairs in a
gram-atom of solution.