Calcium ions in blood trigger clotting. To prevent that in donated blood, sodium oxalate, Na2C2O4, is added to remove calcium ions according to the following equation. C2O42(aq)+Ca2+(aq)CaC2O4(s)Blood contains about 0.10 mg Ca2+/mL. If a 250.0-mL sample of donated blood is treated with an equal volume of 0.160 M Na2C2O4, estimate [Ca2+] after precipitation. (KspCaC2O4=4109)

Potassium hydrogen phthalate, known as KHP (molar mass = 204.22 g/mol), can be obtained in high purity and is used to determine the concentration of solutions of strong bases by the reaction HP(aq)+OH(aq)H2O(l)+P2(aq) If a typical titration experiment begins with approximately 0.5 g KHP and has a final volume of about 100 mL, what is an appropriate indicator to use? The pKa for HP is 5.51.

A solution contains Ca2+ and Pb2+ ions, both at a concentration of 0.010 M. You wish to separate the two ions from each other as completely as possible by precipitating one but not the other using aqueous Na2SO4 as the precipitating agent. (a) Which will precipitate first as sodium sulfate is added, CaSO4 or PbSO4? (b) What will be the concentration of the first ion that precipitates (Ca2+ or Pb2+) when the second, more soluble salt begins to precipitate?

The weak base ethanolamine. HOCH2CH2NH2, can be titrated with HCl. HOCH2CH2NH2(aq)+H3O+(aq)HOCH2CH2NH3+(aq)+H2O(l) Assume you have 25.0 mL of a 0.010 M solution of ethanolamine and titrate it with 0.0095 M HCl. (Kb for ethanolamine is 3.2 107.) (a) What is the pH of the ethanolamine solution before the titration begins? (b) What is the pH at the equivalence point? (c) What is the pH at the halfway point of the titration? (d) Which indicator in Figure 17.11 would be the best choice to detect the equivalence point? (e) Calculate the pH of the solution after adding 5.00, 10.0, 20.0, and 30.0 mL of the acid. (f) Combine the information in parts (a), (b), (c), and (e), and plot an approximate titration curve.

A saturated solution of a slightly soluble electrolyte in contact with some of the solid electrolyte is said to be a system in equilibrium. Explain. Why is such a system called a heterogeneous equilibrium?

A volume of 50 mL of 1.8 M NH3 is mixed with an equal volume of a solution containing 0.95 g of MgCl2. What mass of NH4Cl must be added to the resulting solution to prevent the precipitation of Mg(OH)2?

Consider 0.0010-M solutions of these sparingly soluble solutes in equilibrium with their ions. Predict the effect on each equilibrium if a saturated solution of sodium iodide were added. Explain your prediction in each case. AgI(s) ⇌ Ag+(aq) + I−(aq) PbI2(s) ⇌ Pb2+(aq) + 2 I−(aq)

A student is given 0.930 g of an unknown acid, which can be either oxalic acid, H2C2O4, or citric acid, H3C6H5O7. To determine which acid she has, she titrates the unknown acid with 0.615 M NaOH. The equivalence point is reached when 33.6 mL are added. What is the unknown acid?

Assume you dissolve 0.235 g of the weak acid benzoic acid, C6H5CO2H, in enough water to make 1.00 102 mL of solution and then titrate the solution with 0.108 M NaOH. C6H5CO2H(aq) + OH(aq) C6H5CO2(aq) + H2O() (a) What was the pH of the original benzoic add solution? (b) What are the concentrations of all of the following ions at the equivalence point: Na+, H3O+, OH, and C6H5CO2? (c) What is the pH of the solution at the equivalence point?