(b)在相同熱力學條件下，排序此三種固態物質Pb、PbO2、PbSO4之化學位能的高低，須說明原因。

5. To improve the physical and chemical properties of metal materials, it is common to introduce heteroatoms into the parent material to form a solid solution during metallurgy. Please describe what types of solid solutions that heteroatoms can form, and describe what factors affect the solubility of these heteroatoms in the solid solutions. [10分]