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Problem 104
Calculate the solubility (in grams per 1.00⨉102 mL of solution) of magnesium hydroxide in a solution buffered at pH = 10. How does this compare to the solubility of Mg(OH)2 in pure water?
Problem 105c
Determine if each compound is more soluble in acidic solution than it is in pure water. Explain. a. BaCO3 b. CuS c. AgCl d. PbI2
Problem 107
A solution containing sodium fluoride is mixed with one containing calcium nitrate to form a solution that is 0.015 M in NaF and 0.010 M in Ca(NO3)2. Does a precipitate form in the mixed solution? If so, identify the precipitate.
- A solution containing potassium bromide is mixed with one containing lead acetate to form a solution that is 0.013 M in KBr and 0.0035 M in Pb(C2H3O2)2. Does a precipitate form in the mixed solution? If so, identify the precipitate.
Problem 108
Problem 109
Predict whether a precipitate will form if you mix 75.0 mL of a NaOH solution with pOH = 2.58 with 125.0 mL of a 0.018 M MgCl2 solution. Identify the precipitate, if any.
- What is the minimum concentration of KOH required for precipitation to begin for each of the following cation solutions? a. 0.015 M CaCl2 b. 0.0025 M Fe(NO3)2 c. 0.0018 M MgBr2
Problem 111
Problem 112b
Determine the minimum concentration of the precipitating agent on the right to cause precipitation of the cation from the solution on the left. b. 0.085 M CaI2; K2SO4
Problem 112c
Determine the minimum concentration of the precipitating agent on the right to cause precipitation of the cation from the solution on the left. c. 0.0018 M AgNO3; RbCl
Problem 113a
A solution is 0.010 M in Ba2+ and 0.020 M in Ca2+. a. If sodium sulfate is used to selectively precipitate one of the cations while leaving the other cation in solution, which cation will precipitate first? What minimum concentration of Na2SO4 will trigger the precipitation of the cation that precipitates first?
Problem 113b
A solution is 0.010 M in Ba2+ and 0.020 M in Ca2+. b. What is the remaining concentration of the cation that precipitates first, when the other cation begins to precipitate?
- A solution is 0.022 M in Fe2+ and 0.014 M in Mg2+. a. If potassium carbonate is used to selectively precipitate one of the cations while leaving the other cation in solution, which cation will precipitate first? What minimum concentration of K2CO3 will trigger the precipitation of the cation that precipitates first? b. What is the remaining concentration of the cation that precipitates first when the other cation begins to precipitate?
Problem 114
Problem 115
A solution is made 1.1⨉10-3 M in Zn(NO3)2 and 0.150 M in NH3. After the solution reaches equilibrium, what concentration of Zn2+(aq) remains?
Problem 117
Use the appropriate values of Ksp and Kf to find the equilibrium constant for the reaction. FeS(s) + 6 CN-(aq) ⇌ Fe(CN)64-(aq) + S2-(aq)
- Is the question formulated correctly?
Problem 119
- A buffer is created by combining 150.0 mL of 0.25 M HCHO2 with 75.0 mL of 0.20 M NaOH. Determine the pH of the buffer.
Problem 121
- A buffer is created by combining 3.55 g of NH3 with 4.78 g of HCl and diluting to a total volume of 750.0 mL. Determine the pH of the buffer.
Problem 122
Problem 123
A 1.0-L buffer solution initially contains 0.25 mol of NH3 and 0.25 mol of NH4Cl. In order to adjust the buffer pH to 8.75, should you add NaOH or HCl to the buffer mixture? What mass of the correct reagent should you add?
- To adjust the pH of a 250.0-mL buffer solution initially containing 0.025 mol of HCHO2 and 0.025 mol of NaCHO2 to 4.10, should you add NaOH or HCl, and what mass of the correct reagent should you add?
Problem 124
Problem 125
In analytical chemistry, bases used for titrations must often be standardized; that is, their concentration must be precisely determined. Standardization of sodium hydroxide solutions can be accomplished by titrating potassium hydrogen phthalate (KHC8H4O4), also known as KHP, with the NaOH solution to be standardized. b. The titration of 0.5527 g of KHP required 25.87 mL of an NaOH solution to reach the equivalence point. What is the concentration of the NaOH solution?
- A 0.25-mol sample of a weak acid with an unknown pKa was combined with 10.0 mL of 3.00 M KOH, and the resulting solution was diluted to 1.500 L. The measured pH of the solution was 3.85. What is the pKa of the weak acid?
Problem 127
Problem 128
A 5.55-g sample of a weak acid with Ka = 1.3⨉10-4 was combined with 5.00 mL of 6.00 M NaOH, and the resulting solution was diluted to 750.0 mL. The measured pH of the solution was 4.25. What is the molar mass of the weak acid?
- From the data given—where a 0.552-g sample of ascorbic acid (vitamin C) is dissolved in water to a total volume of 20.0 mL and titrated with 0.1103 M KOH, the equivalence point occurred at 28.42 mL, and the pH of the solution at 10.0 mL of added base was 3.72—determine the molar mass and dissociation constant (Ka) for vitamin C.
Problem 129
- If a hard water solution is saturated with calcium carbonate, what volume of the solution has to evaporate to deposit 1.00 × 10^2 mg of CaCO3, given that one of the main components of hard water is CaCO3, and when hard water evaporates, some of the CaCO3 is left behind as a white mineral deposit?
Problem 131
- If the sodium concentration in blood plasma is 0.140 M, and Ksp for sodium urate is 5.76 * 10^-8, what minimum concentration of urate would result in precipitation?
Problem 132
Problem 133
Pseudogout, a condition with symptoms similar to those of gout (see Problem 126), is caused by the formation of calcium diphosphate (Ca2P2O7) crystals within tendons, cartilage, and ligaments. Calcium diphosphate will precipitate out of blood plasma when diphosphate levels become abnormally high. If the calcium concentration in blood plasma is 9.2 mg/dL, and Ksp for calcium diphosphate is 8.64⨉10-13, what minimum concentration of diphosphate results in precipitation?
Problem 134
Calculate the solubility of silver chloride in a solution that is 0.100 M in NH3.
Problem 135
Calculate the solubility of CuX in a solution that is 0.150 M in NaCN. Ksp for CuX is 1.27⨉10-36.
- The Kb of hydroxylamine, NH2OH, is 1.10 * 10^-8. A buffer solution is prepared by mixing 100.0 mL of a 0.36 M hydroxylamine solution with 50.0 mL of a 0.26 M HCl solution. Determine the pH of the resulting solution.
Problem 137
Problem 138
A 0.867-g sample of an unknown acid requires 32.2 mL of a 0.182 M barium hydroxide solution for neutralization. Assuming the acid is diprotic, calculate the molar mass of the acid.
Problem 139
A 25.0-mL volume of a sodium hydroxide solution requires 19.6 mL of a 0.189 M hydrochloric acid for neutralization. A 10.0-mL volume of a phosphoric acid solution requires 34.9 mL of the sodium hydroxide solution for complete neutralization. Calculate the concentration of the phosphoric acid solution.