Chapter 18, Problem 125E

Pseudogout, a condition with symptoms similar to those of gout (see Problem 124is caused by the formation of calcium diphosphate (Ca₃P₂O₇) crystals within tendons, cartilage, and ligaments. Calcium diphosphate precipitates out of blood plasma when diphosphate levels become abnormally high. If the calcium concentration in blood plasma is 9.2mg/dL and K_spfor calcium diphosphate is $\text{8}{\text{.64 × 10}}^{-13}$ , what minimum concentration of diphosphate results in precipitation?
124. Gout—a condition that results in joint swelling and pain—is caused by the formation of sodium urate (NaC₅H₃N₄O₃) crystals within tendons, cartilage, and ligaments. Sodium urate precipitates out of blood plasma when uric acid levels become abnormally high. This can happen as a result of eating too many rich foods and consuming too much alcohol, which is why gout is sometimes referred to as the “disease of kings.” If the sodium concentration in blood plasma is 0.140 M and K_spfor sodium urate is $\text{5}{\text{.76 × 10}}^{-8}$ , what minimum concentration of urate results in precipitation?