Chapter 16

Cobalt (II) and zinc (II) carbonate have nearly identical \(K_{\mathrm{sp}}\) values. Do they have the same molar solubility? Do they have the same solubility in \(\mathrm{g} / \mathrm{L} ?\)

Which has a higher \(\mathrm{pH}\), a saturated solution of magnesium hydroxide \(\left(K_{\mathrm{sp}}=5.6 \times 10^{-12}\right)\) or a saturated solution of calcium hydroxide \(\left(K_{\mathrm{sp}}=4.7 \times 10^{-6}\right) ?\)

People with diabetes can have elevated levels of two acids in their blood: \(\beta\) -hydroxybutyric acid \(\left(\mathrm{p} K_{\mathrm{a}}=4.72\right)\) and acetoacetic acid \(\left(\mathrm{p} K_{\mathrm{a}}=3.58\right)\) (EQUATION CAN'T COPY) The presence of these acids lowers the \(\mathrm{pH}\) of blood and can serve to diagnose diabetes. a. Which acid yields a solution with the lower \(\mathrm{pH}\) if \(0.100 M\) solutions are prepared? b. Which acid will dissociate to a greater degree? c. What is the pH of a solution that contains \(15.8 \mathrm{mM}\) of acetoacetic acid and \(10.8 \mathrm{m} M\) sodium acetoacetate? d. What is the \(\mathrm{pH}\) of a solution of \(90 \mathrm{mg} / \mathrm{L}\) \beta-hydroxybutyric acid and 90 mg/L \(\beta\) -hydroxybutyrate anion after \(100 \mu \mathrm{L}\) of \(0.100 M\) HCl has been added?

Chickens do not have sweat glands, so when they become overheated, they cool themselves by panting (taking short, quick breaths). This lowers the concentration of \(\mathrm{CO}_{2}\) in their blood. If chickens pant too much, this causes the shells on chickens' eggs to become so thin that they break easily. Eggshells are about \(95 \%\) calcium carbonate. Explain the effect of panting on shell thickness by considering the equilibrium between \(\mathrm{CO}_{2}(a q)\) and \(\mathrm{CO}_{3}^{2-}(a q)\) in blood.

Teeth in both humans and many animals are made of calcium hydroxyphosphate, \(\mathrm{Ca}_{5}\left(\mathrm{PO}_{4}\right)_{3} \mathrm{OH} .\) Veterinarians have noticed that dogs' saliva has a pH that is more basic than the saliva of humans. This fact is suggested as one reason dogs are less subject to tooth decay than people. Explain this suggestion.