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All Textbook Solutions for Chemistry by OpenStax (2015-05-04)

From the equilibrium concentrations given, calculate Ka for each of the weak acids and Kb for each of the weak bases.. (a). NH3:[OH]=3.1103M;[NH4+]=3.1103M;[NH3]=0.533M; (b). HNO2:[H3O+]=0.011M;[NO2]=0.0438M;[HNO2]=1.07M; (c). ( CH3)3N:[( CH 3 )3N]=0.25M;[( CH 3 )3NH+]=4.3103M;[OH]=4.3103M; (d). NH4+:[NH4+]=0.100M;[NH3]=7.5106M;[H3O+]=7.3106M Determine Kb for the nitrite ion, NO2-. In a 0.10-M solution this base is 0.0015% ionized.Determine Ka for hydrogen sulfate ion, HSO4-. In a 0.10-M solution the acid is 29% ionized.Calculate the ionization constant for each of the following acids or bases form the ionization constant of its conjugate base or conjugate acid: (a) F- (b) NH4+ (c) AsO43- (d) (CH3)2 NH2+ (e) NO2- (f) HC2O4- (as a base)Calculate the ionization constant for each of the following acids or bases from the ionization constant of its conjugate base or conjugate acid: (a) HTe- (as a base]. (b) (CH3)3 NH+. (c) HAsO43- (as a base). (d) H02 _ (as a base). (e) C6H5NH3+. (f) HSO3- (as a base)For which of the following solutions must we consider the ionization of water when calculating the pH or pOH? (a) 3108M HNO3. (b) 0.10 g HCl in 1.0 L of solution. (c) 0.00080 g NaOH in 0.50 L of solution. (d) 1107M Ca(OH)2. (e) 0.0245 M KNO3 Even though both NH3 and C6H5NH2 are weak bases, NH3 is a much stronger acid than C6H5NH2. Which of the following is correct at equilibrium for a solution that is initially 0.10 M in NH3 and 0.10 M in C6H5NH2? (a) [OH]=[NH4+] (b) [NH4+]=[C6H5NH3+] (c) [OH]=[C6H5NH3+] (d) [NH3]=[C6H5NH2] (e) both a and b are correct Calculate the equilibrium concentration of the non-ionized acids and all ions in a solution that is 0.25 M in HCO2H and 0.10 M in HClO.Calculate the equilibrium concentration of the non-ionized acids and all ions in a solution that is 0.134 M in HNO2 and 0.120 M in HBrO.Calculate the equilibrium concentration of the nonionized bases and all ions in a solution that is 0.25 M in CH3NH2 and 0.10 M in C5H5N (Kb=1.7109).Calculate the equilibrium concentration of the nonionized bases and all ions in a solution that is 0.115 M in NH3 and 0.100 M in C6H5NH2.Using the Ka value of , place Al(H2O)63+ in the correct location in Figure 14.8. Calculate the concentration of all solute species in each of the following solutions of acids or bases. Assume that the ionization of water can be neglected, and show that the change in the initial concentrations can be neglected, Ionization constants can be found in Appendix H and Appendix I. (a) 0.0092 M HCIO, a weak acid. (b) 0.0784 M C6H5NH2, a weak base. (c) 0.0810 M HCN, a weak acid. (d) 0.11 M (CH3)3N, a weak base. (e) 0.120 M Fe(H2O)62+ a weak acid, Ka=1.6107 Propionic acid, C2H5CO2H (Ka=1.34105), is used in the manufacture of calcium propionate, a food preservative. What is the hydronium ion concentration in a 0.698-M solution of C2H5CO2H?White vinegar is a 5.0% by mass solution of acetic acid in water. If the density of white vinegar is 1.007 g/cm3, what is the pH?The ionization constant of lactic acid, CH3CH(OH)CO2H, an acid found in the blood after strenuous exercise, is 1.36104. If 20.0 g of lactic acid is used to make a solution with a volume of 1.00 L, what is the concentration of hydronium ion in the solution?Nicotine, C10H14N2, is a base that will accept two protons (K1=7107,K2=1.41011). What is the concentration of each species present in a 0.050-M solution of nicotine?The pH of a 0.20-M solution of HP is 1.92. Determine Ka far HF from these data.The pH of a 0.15-M solution of HSO4- is 1.43. Determine Ka for HSO4- from these data.The pH of a 0.10-M solution of caffeine is 11.16. Determine Kb for caffeine from these data: C8H10N4O2(aq)+H2O(l)C8H10N4O2H+(aq)+OH(aq)Tile pH of a solution of household ammonia, a 0.950 M solution of NH3 is 11.612. Determine Kb for NH3 from these data.Determine whether aqueous solutions of the following salts are acidic, basic, or neutral: (a) Al(NO3)3. (b) RbI. (c) KHCO2. (d) CH3NH3Br Determine whether aqueous solutions of the following salts are acidic, basic, or neutral: (a) FeCl3. (b) K2CO3. (c) NH4Br. (d) KClO4 Novocaine, C13H21O2N2Cl, is the salt of the base procaine and hydrochloric acid. The ionization constant for procaine is 7106. 15 a solution of novocaine acidic or basic? What are [H3O+], [OH-], and pH of a 2.0% solution by mass of novocaine, assuming that the density of the solution is 1.0 g/mL.Which of the following concentrations would be practically equal in a calculation of the equilibrium concentrations in a 0.134-M solution of H2CO3, a diprotic acid: [H3O+], [OH-], [H2CO3], [HCO3], [CO32-]? N0 calculations are needed to answer this question.Calculate the concentration of each species present in a 0.050-M solution of H2S.Calculate the concentration of each species present in a 0.010-M solution of phthalic acid, C6H4(CO2H)2. C6H4(CO2H)2(aq)+H2O(l)H3O+(aq)+C6H4(CO2H)(CO2)(aq)Ka=1.1103 C6H4(CO2H)(CO2)(aq)+H2O(l)H3O+(aq)+C6H4(CO2)22(aq)Ka=3.9106 Salicylic acid, HOC6H4CO2H, and its derivatives have been used as pain relievers for a long time. Salicylic acid occurs in small amounts in the leaves, bark, and roots of some vegetation (most notably historically in the bark of the willow tree). Extracts of these plants have been used as medications for centuries. The acid was first isolated in the laboratory in 1838. (a) Bath functional groups of salicylic acid ionize in water, with Ka=1.0103 for the—CO2H group and 4.201013 for the -OH group. What is the pH of a saturated solution of the acid (solubility = 1.8 g/L).. (b) Aspirin was discovered as a result of efforts to produce a derivative of salicylic acid that would not be irritating to the stomach lining. Aspirin is acetylsalicylic acid, CH3CO2C6H4CO2H. The -CO2H functional group is still present, but its acidity is reduced, Ka=3.0104. What is the pH of a solution of aspirin with the same concentration as a saturated solution of salicylic acid (See Part a). (c) Under some conditions, aspirin reacts with water and forms a solution of salicylic acid and acetic acid: CH3CO2C6H4CO2H(aq)+H2O(l)HOC6H4CO2H(aq)+CH3CO2H(aq) i. Which of the acids, salicylic acid or acetic acid, produces more hydronium ions in such a solution? ii. What are the concentrations of molecules and ions in a solution produced by the hydrolysis of 0.50 g of aspirin dissolved in enough water to give 75 mL of solution?The ion HTe- is an amphiprotic species; it can act as either an acid or a base.. (a) What is Ka for the acid reaction of HTe- with H2O?. (b) What is Kb, for the reaction in which HTe- functions as a base in water?. (c) Demonstrate whether or not the second ionization of H2Te can be neglected in the calculation of [HTe-] in a 0.10 M solution of H2Te.Explain why a buffer can be prepared from a mixture of NH4Cl and NaOH but not from NH3 and NaOH.Explain why the pH does not change significantly when a small amount of an acid or a base is added to a solution that contains equal amounts of the acid H3PO4 and a salt of its conjugate base NaH2PO4.Explain why the pH does not change significantly when a small amount of an acid or a base is added to a solution that contains equal amounts of the base NH3 and a salt of its conjugate acid NH4CI.What is [H3O+] in a solution of 0.25 M CH3CO2H and 0.030 M NaCH3CO2?. CH3CO2H(aq)+H2O(l)H3O+(aq)+CH3CO2(aq)Ka=1.8105 What is [H3O+] in a solution of 0.075 M HNO2 and 0.030 M NaNO2?. HNO2(aq)+H2O(l)H3O+(aq)+NO2(aq)Ka=4.5105 What is [OH-] in a solution of 0.125 M CH3NH2 and 0.130 M CH3NH3Cl?. CH3NH2(aq)+H2O(l)CH3NH3+(aq)+OH(aq)Kb=4.4104 What is [OH-] in a solution of 1.25 M NH3 and 0.78 M NH4NO3?. NH3(aq)+H2O(l)NH4+(aq)+OH(aq)Kb=1.8105 What concentration of NH4NO3 is required to make [OH]=1.0105 in a 0.200-M solution of NH3?What concentration of NaF is required to make [H3O+]=2.3104 in a 0.300-M solution of HF?What is the effect on the concentration of acetic acid, hydronium ion, and acetate ion when the following are added to an acidic buffer solution of equal concentrations of acetic acid and sodium acetate: (a) HCl. (b) KCH3CO2. (C) NaCl. (d) KOH. (e) CH3CO2H What is the effect on the concentration of ammonia, hydroxide ion, and ammonium ion when the following are added to a basic buffer solution of equal concentrations of ammonia and ammonium nitrate: (a) KI. (b) NH3. (c) HI. (d) NaOH. (9) NH4Cl What will be the pH of a buffer solution prepared from 0.20 mol NH3, 0.40 mol NH4NO3, and just enough water to give 1.00 L of solution?Calculate the pH of a buffer solution prepared from 0.155 mol of phosphoric acid, 0.250 mole of KH2PO4, and enough water to make 0.500 L of solution.How much solid NaCH3CO23H2O must be added to 0300 L of a 0.50-M acetic acid solution to give a buffer with a pH of 5.00? (Him: Assume a negligible change in volume as the solid is added.)What mass of NH4Cl must be added to 0.750 L of a 0.100-M solution of NH3 to give a buffer solution with a pH of 9.26? (Him: Assume a negligible change in volume as the solid is added.)A buffer solution is prepared from equal volumes of 0.200 M acetic acid and 0.600 M sodium acetate. Use 1.80105 as Ka for acetic acid. (a) What is the pH of the solution? (b) Is the solution acidic or basic? (c) What is the pH of a solution that results when 3.00 mL of 0.034 M HCl is added to 0.200 L of the original buffer?A 5.36-g sample of NH4Cl was added to 25.0 mL of 1.00 M NaOH and the resulting solution diluted to 0.100 L.. (a) What is the pH of this buffer solution?. (b) Is the solution acidic or basic?. (c) What is the pH of a solution that results when 3.00 mL of 0.034 M HCl is added to the solution?Which acid in Table 14.2 is most appropriate for preparation of a buffer solution with a pH of 3.1? Explain your choice.Which acid in Table 14.2 is most appropriate for preparation of a buffer solution with a pH of 3.7? Explain your choice.Which base in Table 14.3 is must appropriate for preparation of a buffer solution with a pH of 10.65? Explain your choice.Which base in Table 14.3 is most appropriate for preparation of a buffer solution with a pH of 9.20? Explain your choice.Saccharin, C7H4NSO3H, is a weak acid (Ka=2.1102). If 0.250 L of diet cola with a buffered pH of 5.48 was prepared from 2.00103 g of sodium saccharide, Na(C7H4NSO3), what are the final concentrations of saccharine and sodium saccharide in the solution?What is the pH of 1.000 L of a solution of 100.0 g of glutamic acid (C5H9NO4, a diprotic acid; K1=8.5105,K2=3.391010) to which has been added 20.0 g of NaOH during the preparation of monosodium glutamate, the ?avoring agent? What is the pH when exactly 1 mol of NaOH per mole of acid has been added?Explain how to choose the appropriate acid-base indicator for the titration of a weak base with a strong acid.Explain why an acid-base indicator changes color over a range of pH values rather than at a specific pH.Why can we ignore the contribution of water to the concentrations of H3O+ in the solutions of following acids: 0.0092 M HClO, a weak acid. 0.0810 M HCN, a weak acid. 0.120 M Fe(H2O)62+ a weak acid, Ka=1.6107 but not the contribution of water to the concentration of OH?Why can we ignore the contribution of water to the concentration of OH- in a solution of the following bases: 0.0784 M C6H5NH2, a weak base. 0.11 M (CH3)3N, a weak base but not the contribution of water to the concentration of H3O+?Draw a curve for a series of solutions of HF. Plot [H3O+]total on the vertical axis and the total concentration of HF (the sum of the concentrations of both the ionized and nonionized HF molecules) on the horizontal axis. Let the total concentration of HF vary from 11010M to 1102M.Draw a curve similar to that shown in Figure 14.23 for a series of solutions of NH3. Plot [OH-] on the vertical axis and the total concentration of NH3 (both ionized and nonionized NH3 molecules) on the horizontal axis. Let the total concentration of NH3 vary from 11010M to 1102M.Calculate the pH at the following points in a titration of 40 mL (0.040 L) of 0.100 M barbituric acid (Ka=9.8105) with 0.100 M KOH. (a) no KOH added. (b) 20 mL of KOH solution added. (c) 39 mL of KOH solution added. (d) 40 mL of KOH solution added. (e) 41 mL of KOH solution added The indicator dinitrophenol is an acid with a Ka of 1.1104. In a 1.0104 -M solution, it is colorless in acid and yellow in base. Calculate the pH range over which it goes from 10% ionized (colorless) to 90% ionized (yellow).Complete the changes in concentrations for each of the following reactions: (a) AgI(s)Ag+(aq)+I(aq)x (b) CaCO3(s)Ca2+(aq)+CO32(aq)x (c) Mg3(OH)2(s)Mg2+(aq)+2OH(aq)x (d) Mg3( PO4)2(s)3Mg2+(aq)+2PO43(aq)x (e) Ca5( PO4)3OH(s)OH(s)5Ca2+(aq)+3PO43(aq)+OH(aq)x Complete the changes in concentrations for each of the following reactions: (a) BaSO4(s)Ba2+(aq)+SO42(aq)x (b) Aa2SO4(s)2Ag+(aq)+SO42(aq)x (c) Al(OH)3(s)Al3+(aq)+3OH(aq)x (d) .Pb(OH)Cl(s)Pb2+(aq)+OH(aq)+Cl(aq)x (e) Ca3( AsO4)2(s)3Ca2+(aq)+2AsO43(aq)3x How do the concentrations of Ag+ and CrO42- in a saturated solution above 1.0 g of solid Ag2CrO4 Change when 100 g of solid Ag2CrO4 is added to the system? Explain.How do the concentrations of Pb2+ and S2- change when K2S is added to a saturated solution of PbS?What additional information do we need to answer the following question: How is the equilibrium of solid silver bromide with a saturated solution of its ions affected when the temperature is raised?Which of the following slightly soluble compounds has a solubility greater than that calculated from its solubility product because of hydrolysis of the anion present: CoSO3, CuI, PbCO3, PbCl2, Tl2S, KCIO4?Which of the following slightly soluble compounds has a solubility greater than that calculated from its solubility product because of hydrolysis of the anion present: AgCl, BaSO4, CaF2, Hg2I2, MnCO3, ZnS, PbS?Write the ionic equation for dissolution and the solubility product (Ksp) expression for each of the following slightly soluble ionic compounds: (a) PbCl2. (b) Ag2S. (c) Sr3(PO4)2. (d) SrSO4 Write the ionic equation for the dissolution and the Ksp expression for each of the following slightly soluble ionic compounds: (a) LaF3. (b) CaCO3. (c) Ag2SO4. (d) Pb(OH)2 The Handbook of Chemistry and Physics (http://openstaxcollege.org/l/16Handbook) gives solubilities of the following compounds in grams per 100 mL of water. Because these compounds are only slightly soluble, assume that the volume does not change on dissolution and calculate the solubility product for each. (a) BaSiF6, 0.026 g/100 mL (contains SiF62- ions) (b) Ce(IO3)4, 1.5102 g/100 mL (c) Gd2(SO4)3, 3.98 g/100 mL (d) (NH4)2PtBr6, 0.59 g/100 mL (contains PtBr62- ions)The Handbook of Chemistry and Physics (http://openstaxcollege.org/l/16Handbook) gives solubilities of the following compounds in grams per 100 mL of water. Because these compounds are only slightly soluble, assume that the volume does not change on dissolution and calculate the solubility product for each. (a) BaSeO4, 0.0118 g/100 mL. (b) Ba(BrO3)2H2O, 0.30 g/100 mL. (c) NH4MgAsO46H2O, 0.033 g/100 mL. (d) La2(MoO4)3, 0.00179 g/100 mL Use solubility products and predict which of the following salts is the most soluble, in terms of moles per liter, in pure water: CaF2, Hg2cl2, PbI2, or Sn(OH)2.Assuming that no equilibria other than dissolution are involved, calculate the molar solubility of each of the following from its solubility product: (a) KHC4H4O6. (b) PbI2. (c) Ag4[Fe(CN)6], a salt containing the Fe(CN)4- ion. (d) Hg2I2 Assuming that no equilibria other than dissolution are involved, calculate the molar solubility of each of the following from its solubility product: (a) Ag2SO4. (b) PbBr2. (c) AgI. (d) CaC2O4H2O Assuming that no equilibria other than dissolution are involved, calculate the concentration of all solute species in each of the following solutions of salts in contact with a solution containing a common ion. Show that changes in the initial concentrations of the common ions can be neglected. (a) AgCl(s) in 0.025 M NaCl. (b) CaF2(s) in 0.00133 M KF. (c) Ag2SO4(s) in 0.500 L of a solution containing 19.50 g of K2SO4. (d) Zn(OH)2(s) in a solution buffered at a pH of 11.45 Assuming that no equilibria other than dissolution are involved, calculate the concentration of all solute species in each of the following solutions of salts in contact with a solution containing a common ion. Show that changes in the initial concentrations of the common ions can be neglected. (a) TlCl(s) in 1.250 M HCl. (b) PbI2(s) in 0.0355 M Cal2. (c) Ag2CrO4(s) in 0.225 L of a solution containing 0.856 g of K2CrO4. (d) Cd(OH)2(s) in a solution buffered at a pH of 10.995 Assuming that no equilibria other than dissolution are involved, calculate the concentration of all solute species in each of the following solutions of salts in contact with a solution containing a common ion. Show that it is not appropriate to neglect the changes in the initial concentrations of the common ions. (a) TICl(s) in 0.025 M TlNO3. (b) BaF2(s) in 0.0313 M KF. (c) MgC2O4 in 2.250 L of a solution containing 8.156 g of Mg(NO3)2. (d) Ca(OH)2(s) in an unbuffered solution initially with a pH of 12.700 Explain why the changes in concentrations of the common ions in Exercise 15.17 can be neglected.Explain why the Changes in concentrations of the common ions in Exercise 15.18 cannot be neglected.Calculate the solubility of aluminum hydroxide, Al(OH)3, in a solution buffered at pH 11.00.Refer to Appendix J for solubility products for calcium salts. Determine which of the calcium salts listed is most soluble in moles per liter and which is most soluble in grams per liter.Most barium compounds are very poisonous; however, barium sulfate is often administered internally as an aid in the X-ray examination of the lower intestinal tract (Figure 15.4). This use of BaSO4 is possible because of its low solubility. Calculate the molar solubility of BaSO4 and the mass of barium present in 1.00 L of water saturated with BaSO4.Public Health Service standards for drinking water set a maximum of 250 mg/L (2.620103M) of SO42- because of its cathartic action (it is a laxative). Does natural water [hat is saturated with CaSO4 (gyp" water) as a result or passing through soil containing gypsum, CaSO42H2O, meet these standards? What is the concentration of SO42- in such water?Perform the following calculations: (a) Calculate [Ag+] in a saturated aqueous solution of AgBr. (b) What will [Ag+] be when enough KBr has been added to make [Br]=0.050M ?. (c) What will [Br-] be when enough AgNO3 has been added to make [Ag+]=0.020M?The solubility product of CaSO42H2O is 2.4105. What mass of this salt will dissolve in 1.0 L of 0.010 M SO42-?Assuming that no equilibria other than dissolution are involved, calculate the concentrations of ions in a saturated solution of each of the following (see Appendix J for solubility products). (a) TlCl. (b) BaF2. (c) Ag2CrO4. (d) CaC2O4H2O (e) the mineral anglesite, PbSO4 Assuming that no equilibria other than dissolution are involved, calculate the concentrations of ions in a saturated solution of each of the following (see Appendix J for solubility products): (a) Agl. (b) Ag2SO4. (c) Mn(OH)2. (d) Sr(OH)28H2O (e) the mineral brucite, Mg(OH)2 The following concentrations are found in mixtures of ions in equilibrium with slightly soluble solids. From the concentrations given, calculate Ksp for each of the slightly soluble solids indicated: (a) AgBr:[Ag+]=5.7107M,[Br]=5.7107M (b) CaCO3:[Ca2+]=5.3103M,[CO32]=9.0107M (c) PbF2:[Pb2+]=2.1103M,[F]=4.2103M (d) Ag2CrO4:[Ag+]=5.3105M,3.2103M (e) InF3:[In3+]=2.3103M,[F]=7.0103M The following concentrations are found in mixtures of ions in equilibrium with slightly soluble solids. From the concentrations given, calculate Ksp for each of the slightly soluble solids indicated: (a) TlCl:[Tl+]=1.21102M,[Cl]=1.2102M (b) Ce(IO3)4:[Ce4+]=1.8104M,[IO3]=2.61013M (c) Gd2(SO4)3:[Gd3+]=0.132M,[SO42]=0.198M (d) Ag2SO4:[Ag+]=2.40102M,[SO42]=2.05102M (e) BaSO4:[Ba2+]=0.500M,[SO42]=2.161010M Which of the following compounds precipitates from a solution that has the concentrations indicated? (See Appendix J for Ksp values.) (a) KClO4:[K+]=0.01M,[ClO4]=0.01M (b) K2PtCl6:[K+]=0.01M,[PtCl62]=0.01M (c) PBI2:[Pb2+]=0.003M,[I]=1.3103M (d) Ag2S:[Ag+]=11010M,[S2]=11013M Which of the following compounds precipitates from a solution that has the concentrations indicated? (See Appendix J for Ksp values.) (a) CaCO3:[Ca2+]=0.003M,[CO32]=0.003M (b) CO(OH)2:[CO2+]=0.01M,[OH]=1107M (c) CaHPO4:[Ca2+]=0.01M,[HPO42]=2106M (d) Pb3(PO4)2:[Pb2+]=0.01M,[PO43]=11013M Calculate the concentration of Tl+ when TICl just begins to precipitate from a solution that is 0.0250 M in Cl-.Calculate the concentration of sulfate ion when BaSO4 just begins to precipitate from a solution that is 0.0758 M in Ba2+.Calculate the concentration of Sr2+ when SrF2 starts to precipitate from a solution that is 0.0025 M in F-.Calculate the concentration of PO43- when Ag3PO4 starts to precipitate from a solution that is 0.0125 M in Ag+.Calculate the concentration of F- required to begin precipitation of CaF2 in a solution that is 0.010 M in Ca2+.Calculate the concentration] of Ag+ required to begin precipitation of Ag2CO3 in a solution that is 2.50106M in CO32-.What [Ag+] is required to reduce [CO32-] to 8.2104M by precipitation of Ag2CO3?What [F-] is required to reduce [Ca2+] to 1.0104M by precipitation of CaF2?A volume of 0.800 L of a 2104 -M Ba(NO3)2 solution is added to 0.200 L of 5104M Li2SO4. Does BaSO4 precipitate? Explain your answer.Perform these calculations for nickel(II) carbonate. (a) With what volume of water must a precipitate containing NiCO3 be washed to dissolve 0.100 g of this compound? Assume that the wash water becomes saturated with NiCO3(Ksp=1.36107). (b) If the NiCO3 were a contaminant in a sample of COCO3(Ksp=1.01012), what mass of COCO3 would have been lost? Keep in mind that both NiCO3 and COCO3 dissolve in the same solution.Iron concentrations greater than 5.4106 M in water used for laundry purposes can cause staining. What [OH-] is required to reduce [Fe2+] to this level by precipitation of Fe(OH)2?A solution is 0.010 M in both Cu2+ and Cd2+. What percentage of Cd2+ remains in the solution when 99.9% of the Cu2+ has been precipitated as CuS by adding sulfide?A solution is 0.15 M in both Pb2+ and Ag+. If Cl- is added to this solution, what is [Ag+] when PbCl2 begins to precipitate?What reagent might be used to separate the ions in each of the following mixtures, which are 0.1 M with respect to each ion? In some cases it may be necessary to control the pH. (Hint: Consider the KSP values given in Appendix J.) (a) Hg22+ and Cu2+. (b) SO42- and Cl-. (c) Hg2+ and CO2+. (d) Zn2+ and Sr2+. (e) Ba2+ and Mg2+. (f) CO32- and OH-A solution contains 1.0105 mol of KBr and 0.10 mol of KCl per liter. AgNO3 is gradually added to this solution. Which forms first, solid AgBr or solid AgCl?A solution contains 1.0102 mol of Kl and 0.10 mol of KCl per liter. AgNO3 is gradually added to this solution. Which forms first, solid AgI or solid AgCl?The calcium ions in human blood serum are necessary for coagulation (Figure 15.5). Potassium oxalate, K2C2O4, is used as an anticoagulant when a blood sample is drawn for laboratory tests because it removes the calcium as a precipitate of CaC2O4H2O. It is necessary to remove all but 1.0% of the Ca2+ in serum in order to prevent coagulation. If normal blood serum with a buffered pH of 7.40 contains 9.5 mg of Ca2+ per 100 mL of serum, what mass of K2C2O4 is required to prevent the coagulation of a 10 mL blood sample that is 55% serum by volume? (All volumes are accurate to two significant figures. Note that the volume of serum in a 10-mL blood sample is 5.5 mL. Assume that the KSp value for CaC2O4 in serum is the same as in water.) Figure 15.5 Anticoagulants can be added to blood that will combine with the Ca2+ ions in blood serum and prevent the blood from clotting. (credit: modification of work by Neeta Lind)About 50% of urinary calculi (kidney stones) consist of calcium phosphate, Ca3(PO4)2. The normal mid-range calcium content excreted in the urine is 0.10 g of Ca2+ per day. The normal mid-range amount of urine passed may be taken as 1.4 L per day. What is the maximum concentration of phosphate of that urine can contain before a calculus begins to form?The pH of normal urine is 6.30, and the total phosphate concentration ([PO43]+[H2PO42]+[H2PO4]+[H3PO4]) is 0.020 M. What is the minimum concentration of Ca2+ necessary to induce kidney stone formation? (See Exercise 15.49 for additional information.)Magnesium metal (a component of alloys used in aircraft and a reducing agent used in the production of uranium, titanium, and other active metals) is isolated from sea water by the following sequence of reactions: Mg2+(aq)+Ca(OH)2(aq)Mg(OH)2(s)+Ca2+(aq)Mg(OH)2(s)+2HCl(aq)MgCl2(s)+2H2O(l)MgCl2(l)electrolysisMg(s)+Cl2+Cl2(g) Sea water has a density of 1.026 g/cm3 and contains 1272 parts per million of magnesium a5 Mg2+(aq) by mass. What mass, in kilograms, of Ca(OH)2; is required to precipitate 99.9% of the magnesium in 1.00103 L of sea water?Hydrogen sulfide is bubbled into a solution that is 0.10 M in both Pb2+ and Fe2+ and 0.30 M in HCl. After the solution has come to equilibrium it is saturated with H2S ( H2S[H2S]=0.10M). What concentrations of Pb2+ and Fe2+ remain in the solution? For a saturated solution of H2S we can use the equilibrium: H2S(aq)+2H2O(l)2H3O+(aq)+S2(aq)K=1.01026 (Hint: The [H3O+] changes as metal sulfides precipitate.)Perform the following calculations involving concentrations of iodate ions: (a) The iodate ion concentration of a saturated solution of La(IO3)3 was found to be 3.1103 mol/L, Find the Ksp. (b)Find the concentration of iodate ions in a saturated solution of Cu(IO3)2(Ksp=7.4108).Calculate the molar solubility of AgBr in 0.035 M NaBr (KSP=51013).How many grams of Pb(OH)2 will dissolve in 500 mL of a 0.050-M PbCl2 solution (KSP=1.21015)?Use the simulation (http://openstaxcollege.org/l/16solublesalts) from the earlier Link to Learning to complete the following exercise:. Using 0.01 g CaF2, give the Ksp, values found in a 0.2-M solution of each of the salts. Discuss why the values Change as you change soluble salts.How many grams of Milk of Magnesia, Mg(OH)2 (s) (58.3 g/mol), would be soluble in 200 mL of water. (KSP=7.11012). Include the ionic reaction and the expression for Ksp, in your answer. (Kw=11014=[H3O+][HO]).Two hypothetical salts, LM2 and LQ, have the same molar solubility in H2O. If Ksp for LM2 is 3.20105, what is the Ksp, value for LQ?Which of the following carbonates will form first? Which of the following will form last? Explain. (a) MgCO3Ksp=3.5108 (b) CaCO3Ksp=4.2107 (c) SrCO3Ksp=3.9109 (d) BaCO3Ksp=4.4105 (e) MnCO3Ksp=5.1109 How many grams of Zn(CN)2(s) (117.44 g/mol) would be soluble in 100 mL of H2O? Include the balanced reaction and the expression for Ksp in your answer. The KSP value for Zn(CN)2(s) is 3.01016.Under what circumstances, if any, does a sample of solid AgCl completely dissolve in pure water?Explain why the addition of NH3 or HNO3 to a saturated solution of Ag2CO3 in contact with solid Ag2CO3 increases the solubility of the solid.Calculate the cadmium ion concentration, [Cd2+], in a solution prepared by mixing 0.100 L of 0.0100 M Cd(NO3)2 with 1.150 L of 0.100 NH3(aq).Explain why addition of NH3 or HNO3 to a saturated solution of Cu(OH)2 in contact with solid Cu(OH)2 increases the solubility of the solid.Sometimes equilibria fur complex ions are described in terms of dissociation constants. Kd . For the complex ion AlF63- the dissociation reaction is: AlF63Al3++6F and Kd=[Al3+][F]6[AlF63]=21024 Calculate the value of the formation constant, Kf, for AlF63-.Using the value of the formation constant for the complex ion Co(NH3)62+ calculate the dissociation constant.Using the dissociation constant, Kd=7.81018, calculate the equilibrium concentrations of Cd2+ and CN- in a 0.250-M solution of Cd(CN)42-.Using the dissociation constant, Kd=3.41015, calculate the equilibrium concentrations of Zn2+ and OH- in a 0.0465-M solution of Zn(OH)42-.Using the dissociation constant, Kd=2.21034, calculate the equilibrium concentrations of Co3+ and NH3 in a 0.500-M solution of Co(NH3)63+.Using the dissociation constant kd=1*10-44 calculate the equilibrium concentrations of Fe3+ and CN- in a 0.333-M solution of Fe(CN)63-.Calculate the mass of potassium cyanide ion that must be added to 100 mL of solution to dissolve 2.0102 mol of silver cyanide, AgCN.Calculate the minimum concentration of ammonia needed in 1.0 L of solution to dissolve 3.0103 mol of silver bromide.A roll of 35-mm black and white photographic film contains about 0.27 g of unexposed AgBr before developing. What mass of Na2S2O35H2O (sodium thiosulfate pent hydrate or hypo) in 1.0 L of developer is required to dissolve the AgBr as Ag(S2O3)23- (Kf=4.71013)?We have seen an introductory definition of an acid: An acid is a compound that reacts with water and increases the amount of hydronium ion present. In the Chapter on acids and bases, we saw two more definitions of acids: a compound that donates a proton (a hydrogen ion, H+) to another compound is called a Bronsted-Lowry acid, and a Lewis acid is any species that can accept a pair of electrons. Explain why the introductory definition is a macroscopic definition, while the Bronsted-Lomy definition and the Lewis definition are microscopic definitions.Write the Lewis structures of the reactants and product of each of the following equations, and identify the Lewis acid and the Lewis base in each: (a) CO2+OHHCO3 (b) B(OH)3+OHB(OH)4 (c) I+I2I3 (d) AlCl3+ClAlCl4 (use Al-Cl single bonds) (e) .O2+SO3SO42 Write the Lewis structures of the reactants and product of each of the following equations, and identify the Lewis acid and the Lewis base in each: (a) CS2+SHHCS3 (b) BF3+FBF4 (c) I+SnI2SnI3 (d) Al(OH)3+OHAl(OH)4 (e) F+SO3SFO3 Using Lewis structures, write balanced equations for the following reactions: (a) HCI(g)+PH3(g) (b) H3O++CH3 (c) CaO+SO3 (d) NH4++C2H5O Calculate [HgCl42-] in a solution prepared by adding 0.0200 mol of NaCl to 0.250 L of a 0.100-M HgCI2 solution.In a titration of cyanide ion, 28.72 mL of 0.0100 M AgNO3 is added before precipitation begins. [The reaction of Ag+ with CN- goes to completion, producing the Ag(CN)2- complex. Precipitation of solid AgCN takes place when excess Ag+ is added to the solution, above the amount needed to complete the formation of Ag(CN)2-. How many grams of NaCN were in the original sample?What are the concentrations of Ag+, CN-, and Ag(CN)2- in a saturated solution of AgCN?In dilute aqueous solution HF acts as a weak acid. However, pure liquid HF (boiling point = 19.5 C) is a strong acid. In liquid HF, HNO3 acts like a base and accepts protons. The acidity of liquid HF can be increased by adding one of several inorganic fluorides that ale Lewis acids and accept F- ion (for example, BF3 or SbF5]. Write balanced chemical equations for the reaction of pure HNO3 with pure HF and of pure HF with BF3.The simplest amino acid is glycine, H2NCH2CO2H. The common feature of amino acids is that they contain the functional groups: an amine group, -NH2, and a carboxylic acid group, -CO2H. An amino acid can function as either an acid or a base. For glycine, the acid strength of the carboxyl group is about the same as that of acetic acid. CH3CO2H, and the base strength of the amino group is slightly greater than that of ammonia, NH3. (a) Write the Lewis structures of the ions that form when glycine is dissolved in 1 M HCl and in 1 M KOH. (b) Write the Lewis structure of glycine when this amino acid is dissolved in water. (Hint: Consider the relative base strengths of the -NH2 and -CO2- groups.)Boric acid, H3303, is not a Bronsted-Lowry acid but a Lewis acid.. (a) Write an equation for its reaction with water. (b) Predict the shape of the anion thus formed. (c) What is the hybridization 0n the boron consistent with the shape you have predicted?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?Calculate the equilibrium concentration of Ni2+ in a 1.0-M solution [Ni(NH3)6](NO3)2.Calculate the equilibrium concentration of Zn2+ in a 0.30-M solution of Zn(CN)42-.Calculate the equilibrium concentration of Cu2+ in a solution initially with 0.050 M Cu2+ and 1.00 M NH3.Calculate the equilibrium concentration of Zn2+ in a solution initially with 0.150 M Zn2+ and 2.50 M CN-.Calculate the Fe3+ equilibrium concentration when 0.0888 mole of K3[Fe(CN)6] is added to a solution with 0.0.00010 M CN-.Calculate the CO2+ equilibrium concentration when 0.100 mole of [CO(NH3)6](NO3)2 is added to a solution with 0.025 M NH3. Assume the volume is 1.00 L.The equilibrium constant for the reaction Hg2+(aq)+2Cl(aq)HgCl2(aq) is 1.61013, Is HgCl2 a strong electrolyte or a weak electrolyte? Mm are the concentrations of Hg2+ and Cl- in a 0.015-M solution of HgCl2?Calculate the molar solubility of Sn(OH)2 in a buffer solution containing equal concentrations of NH3 and. NH4+.Calculate the molar solubility of Al(OH)3 in a buffer solution with 0.100 M NH3 and 0.400 M NH4+.What is the molar solubility of CaF2 in a 0.100-M solution of HF? Ka for HF=7.2104.What is the molar solubility of BaSO4 in a 0.250-M solution of NaHSO4? Ka for HSO4=1.2102.What is the molar solubility of Tl(OH)3 in a 0.10-M solution of NH3?What is the molar solubility of Pb(OH)2 in a 0.138-M solution of CH3NH2?A solution of 0.075 M CoBr2 is saturated with H2S([H2S]=0.10M). What is the minimum pH at which CoS begins to precipitate?. CoS(s)Co2+(aq)+S2(aq)Ksp=4.51027 H2S(aq)+2H2O(l)2H3O+(aq)+S2(aq)K=1.01026 A 0.125-M solution of 0.075 Mn(NO3)2 is saturated with H2S([H2S]=0.10M). At what pH does Mns begin to precipitate?. MnS(s)Mn2+(aq)+S2(aq)Ksp=4.31022 H2S(aq)+2H2O(l)2H3O+(aq)+S2(aq)K=1.01026 Calculate the molar solubility of BaF2 in a buffer solution containing 0.20 M HF and 0.20 M NaF.Calculate the molar solubility of CdCO3 in a buffer solution containing 0.115 M Na2CO3 and 0.120 M NaHCO3 To a 0.10-M solution of Pb(NO3)2 is added enough HF(g) to make [HF]=0.10M. (a) Does PbF2 precipitate from this solution? Show the calculations that support your conclusion. (b) What is the minimum pH at which PbF2 precipitates?Calculate the concentration of Cd2+ resulting from the dissolution of CdCO3 in a solution that is 0.250 M in CH3CO2H, 0.375 M in NaCH3CO2, and 0.010 M in H2CO3.Both AgCl and Agl dissolve in NH3.. (a) What mass of AgI dissolves in 1.0 L of 1.0 M NH3?. (b) VNhat mass of AgCl dissolves in 1.0 L of 1.0 M NH3?Calculate the volume of 1.50 M CH3CO2H required to dissolve a precipitate composed of 350 mg each of CaCO3, SrCO3, and BaCO3.Even though Ca(OH)2 is an inexpensive base, its limited solubility restricts its use. What is the pH of a saturated solution of Ca(OH)2?What mass of NaCN must be added to 1 L of 0.010 M Mg(NO3)2 in order to produce the first trace of Mg(OH)2?Magnesium hydroxide and magnesium citrate function as mild laxatives when they reach the small intestine. Why do magnesium hydroxide and magnesium citrate, two very different substances, have the same effect in your small intestine. (Hint: The contents of the small intestine are basic.)The following question is taken from a Chemistry Advanced Placement Examination and is used with the permission of the Educational Testing Service. Solve the following problem: MgF2(s)Mg2+(aq)+2F(aq) In a saturated solution of MgF2 at 18 C, the concentration of Mg2+ is 1.21103M . The equilibrium is represented by the preceding equation. (a) Write the expression for the solubility-product constant, Ksp, and calculate its value at 18 C. (b) Calculate the equilibrium concentration of Mg2+ in 1.000 L of saturated MgF2 solution at 18 C to which 0.100 mol of solid KF has been added. The KF dissolves completely. Assume the volume change is negligible. (c) Predict whether a precipitate of MgF2 will form when 100.0 mL of a 3.00103 -M solution of Mg(NO3)2 is mixed with 200.0 mL of a .2.00103 -M solution of NaF at 18 C. Show the calculations to support your prediction.. (d) At 27 C the concentration of Mg2+ in a saturated solution of MgF2 is 1.17103M . Is the dissolving of MgF2 in water all endothermic or an exothermic process? Give an explanation to support your conclusion.Which of the following compounds, when dissolved in a 0.01-M solution of HClO4, has a solubility greater than in pure water: CuCl, CaCO3, MnS, PbBr2, CaF2? Explain your answer.Which of the following compounds, when dissolved in a 0.01-M solution of HClO4, has a solubility greater than in pure water: AgBr, BaF2, Ca3(PO4)2, ZnS, PbI2? Explain your answer.What is the effect on the amount of solid Mg(OH)2 that dissolves and the concentrations of Mg2+ and OH- when each of the following are added to a mixture of solid Mg(OH)2 and water at equilibrium? (a) Mgcl2. (b) KOH. (c) HClO4. (d) NaNO3. (e) Mg(OH)2 What is the effect on the amount of CaHPO4 that dissolves and the concentrations of Ca2+ and HPO4- when each of the following are added to a mixture of solid CaHPO4 and water at equilibrium? (a) CaCl2. (b) HCl. (c) KClO4. (d) NaOH. (e) CaHPO4 Identify all chemical species present in an aqueous solution of Ca3(PO4)2 and list these species in decreasing order of their concentrations. (Hint: Remember that the PO43- ion is a weak base.)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?What is a spontaneous reaction?What is a nonspontaneous reaction?Indicate whether the following processes are spontaneous or nonspontaneous. (a) Liquid water freezing at a temperature below its freezing point (b) Liquid water freezing at a temperature above its freezing point (c) The combustion of gasoline (d) A ball thrown into the air (e) A raindrop falling to the ground (f) Iron rusting in a moist atmosphere A helium-filled balloon spontaneously deflates overnight as He atoms diffuse through the wall of the balloon. Describe the redistribution of matter and/or energy that accompanies this process.Many plastic materials are organic polymers that contain carbon and hydrogen. The oxidation of these plastics in air to farm carbon dioxide and water is a spontaneous process; however, plastic materials tend to persist in the environment. Explain.In Figure 16.8 all possible distributions and microstates are shown for four different particles shared between two boxes. Determine the entropy change, S, if the particles are initially evenly distributed between the two boxes, but upon redistribution all end up in Box (b).In Figure 16.8 all of the possible distributions and microstates are shown for four different particles shared between two boxes. Determine the entropy change, S, for the system when it is converted from distribution (b) to distribution (d).How does the process described in the previous item relate to the system shown in Figure 16.4?Consider a system similar to the one in Figure 16.8, except that it contains six particles instead of four. What is the probability of having all the particles in only one of the two boxes in the case? Compare this with the similar probability for the system of four particles that we have derived to be equal to 18 . What does this comparison tell us about even larger systems?Consider the system shown in Figure 16.9. What is the change in entropy for the process where the energy is initially associated only with particle A, but in the final state the energy is distributed between two different particles?Consider the system shown in Figure 16.9. What is the change in entropy for the process where the energy is initially associated with particles A and B, and the energy is distributed between two particles in different boxes (one in A-B, the other in C-D)?Arrange the following sets of systems in order of increasing entropy. Assume one mole of each substance and the same temperature for each member of a set.. (a) H2(g), HBrO4(g), HBr(g). (b)H2O(l), H2O(g), H2O(s). (c) He(g), Cl2(g), P4(g)At room temperature, the entropy of the halogens increases from I2 to Br2 to Cl2. Explain.Consider two processes: sublimation of I2(s) and melting of I2(s) (Note: the latter process can occur at the same temperature but somewhat higher pressure). I2(s)I2(g)I2(s)I2(l) Is S positive or negative in these processes? In which of the processes will the magnitude of the entropy change be greater?Indicate which substance in the given pairs has the higher entropy value. Explain your choices.. (a) C2H5OH(l) or C3H7OH(l). (b) C2H5OH(l) or C2H5OH(g). (c) 2H(g) or H(g)Predict the sign of the entropy change for the following processes.. (a) An ice cube is warmed to near its melting point. (b) Exhaled breath forms fog on a cold morning. (c) Snow melts.Predict the sign of the entropy change for the following processes. Give a reason for your prediction.. (a) Pb2+(aq)+S2(aq)Pbs(s). (b) 2Fe(s)+32O2(g)Fe2O2(s) (C) 2C6H14(l)+19O2(g)14H2O(g)+12CO2(g)Write the balanced chemical equation for the combustion of methane, CH4(g), to give carbon dioxide and water vapor. Explain why it is difficult to predict whether S is positive or negative for this chemical reaction.Write the balanced chemical equation for the combustion of benzene, C6H6(l), to give carbon dioxide and water vapor. Would you expect S to be positive or negative in this process?What is the difference between S, S , and S 298 for a Chemical change?Calculate S298 for the following changes. (a) SnCl4(l)SnCl4(g) (b) CS2(g)CS2(l) (c) Cu(s)Cu(g) (d) H2O(l)H2O(g) (e) 2H2(g)+O2(g)2H2O(l) (f) 2HCI(g)+Pb(s)PbCl2(s)+H2(g) (g) Zn(s)+CuSO4(s)Cu(s)+ZnSO4(s)Determine the entropy change for the combustion of liquid ethanol, C2H5OH, under the standard conditions to give gaseous carbon dioxide and liquid water.Determine the entropy change for the combustion of gaseous propane, C3H8, under the standard conditions to give gaseous carbon dioxide and water.Thermite reactions have been used for welding metal parts such as railway rails and in metal refining. One such thermite reaction is Fe2O3(s)+2Al(s)Al2O3(s)+2Fe(s). Is the reaction spontaneous at room temperature under standard conditions? During the reaction, the surroundings absorb 851.8 kJ/mol of heat.Using the relevant S 298 values listed in Appendix G, calculate S 298 for the following changes: (a) N2(g)+3H2(g)2NH3(g) (b) N2(g)+52O2(g)N2O5(g)From the following information, determine S298 for the following: N(g)+O(g)NO(g) S298=? N2(g)+O2(g)2NO(g)S298=24.8J/K N2(g)2N(g)S298=115.0J/K O2(g)2O(g)S298=117.0J/K By calculating Suniv, at each temperature, determine if the melting of 1 mole of NaCl(s) is spontaneous at 500 C and at 700 C.. SNaCl(s)=72.11JmolKSNaCl(l)=95.06JmolK HFusion=27.95kJ/mol What assumptions are made about the thermodynamic information (entropy and enthalpy values) used to solve this problem?Use the standard entropy data in Appendix G to determine the change in entropy for each of the reactions listed in Exercise 16.33. All the processes occur at the standard conditions and 25 C.Use the standard entropy data in Appendix G to determine the change in entropy for each of the reactions listed in Exercise 16.34. All the processes occur at the standard conditions and 25 C.What is the difference between G, G, and G 298 for a chemical Change?A reaction has H298=100 kj/mol and S298=250 J/mol K. Is the reaction spontaneous at room temperature? If not, under what temperature conditions will it become spontaneous?Explain what happens as a reaction starts with G0 (negative) and reaches the point where G=0.Use the standard free energy of formation data in Appendix G to determine the free energy change for each of the following reactions, which are run under standard state conditions and 25 C. Identify each as either spontaneous or nonspontaneous at these conditions. (a) MnO2(s)Mn(s)+O2(g) (b) H2(g)+Br2(l)2HBr(g) (c) Cu(s)+S(g)CuS(s) (d) 2LiOH(s)+CO2(g)Li2CO3(s)+H2O(g) (e) CH4(g)+O2(g)C(s,graphite)+2H2O(g) (f) CS2(g)+3Cl2(g)CCl4(g)+S2Cl2(g)Use the standard free energy data in Appendix G to determine the free energy change for each of the following reactions, which are run under standard state conditions and 25 C. Identify each as either spontaneous or nonspontaneous at these conditions. (a) C(s,graphite)+O2(g)CO2(g) (b) O2(g)+N2(g)2NO(g) (c) 2Cu(s)+S(g)Cu2S(s) (d) CaO(s)+H2O(l)Ca(OH)2(s) (e) Fe2O3(g)+3CO(g)2Fe(s)+3CO2(g) (f) CaSO42H2O(s)CaSO4(s)+2H2O(g)Given: P4(s)+5O2(g)P4O10(s)G298=2697.0kJ/mol 2H2(g)+O2(g)2H2O(g)G298=457.18kJ/mol 6H2O(g)+P4O10(s)4H3PO4(l)G298=428.66kJ/mol (a) Determine the standard free energy of formation, Gf, for phosphoric acid. (b) How does your calculated result compare to the value in Appendix G? Explain.Is the formation of ozone (O3(g)) from oxygen (O2(g)) spontaneous at room temperature under standard state conditions?Consider the decomposition of red mercury(II) oxide under standard state conditions.. 2HgO(s,red)2Hg(l)+O2(g) (a) Is the decomposition spontaneous under standard state conditions? (b) Above what temperature does the reaction become spontaneous?Among other things, an ideal fuel for the control thrusters of a space vehicle should decompose in a spontaneous exothermic reaction when exposed to the appropriate catalyst. Evaluate the following substances under standard state conditions as suitable candidates for fuels. (a) Ammonia: 2NH3(g)N2(g)+3H2(g) (b) Diborane: B2H6(g)2B(g)+3H2(g) (c) Hydrazine: N2H4(g)N2(g)+2H2(g) (d) Hydrogen peroxide: H2O2(l)H2O(g)+12O2(g)Calculate G for each of the following reactions from the equilibrium constant at the temperature given. (a) N2(g)+O2(g)2NO(g)T=2000CKp=4.1104 (b) H2(g)+I2(g)2HI(g)T=400CKp=50.0 (c) CO2(g)+H2(g)CO(g)+H2O(g)T=980CKp=1.67 (d) CaCO3(s)CaO(s)+CO2(g)T=900CKp=1.04 (e) HF(aq)+H2O(l)H3O+(aq)+F(aq)T=25CKp=7.2104 (f) AgBr(s)Ag++Br(aq)T=25CKp=3.31013 Calculate G for each of the following reactions from the equilibrium constant at the temperature given. (a) Cl2(g)+Br2(g)2BrCl(g)T=25CKp=4.7102 (b) 2SO2(g)+O2(g)2SO3(g)T=500CKp=48.2 (c) H2O(l)H2O(g)T=60CKp=0.196atm (d) CoO(s)+CO(g)CO(s)+CO2(g)T=550CKp=4.90102 (e) CH3NH2(aq)+H2O(l)CH3NH3+(aq)+OH(aq)T=25CKp=4.4104 (f) PbI2(s)Pb2++2I(aq)T=25CKp=8.7109 Calculate the equilibrium constant at 25 C for each of the following reactions from the value G given. (a) O2(g)+2F2(g)2OF2(g)G=9.2kJ (b) I2(s)+Br2(l)2IBr(g)G=7.3kJ (c) 2LiOH(s)+CO2(g)Li2CO3(s)+H2O(g)G=79kJ (d) N2O3(g)NO(g)+NO2(g)G=1.6kJ (e) SnCl4(l)SnCl4(l)G=8.0kJ Calculate the equilibrium constant at 25 C for each of the following reactions from the value G given. (a) I2(s)+Cl2(l)2ICl(g)G=10.88kJ (b) H2(g)+I2(s)2HI(g)G=3.4kJ (c) CS2(g)+3Cl2(g)CCl4(g)+S2Cl2(g)G=39kJ (d) 2SO2(g)+O2(g)2SO3(g)G=141.82kJ (e) CS2(g)CS2(l)G=1.88kJ Calculate the equilibrium constant temperature given. (a) O2(g)+2F2(g)2F2O(g)(T=100C) (b) I2(s)+Br2(l)2IBr(g)(T=100C) (c) 2LiOH(s)+CO2(g)Li2CO3(g)+H2O(g)(T=575C) (d) N2O3(g)NO(g)+NO2(g)(T=100C) (e) SnCl4(l)SnCl4(g)(T=200C)Calculate the equilibrium constant temperature given. (a) I2(s)+Cl2(g)2ICl(g)(T=100C) (b) H2(g)+I2(s)2HI(g)(T=0.0C) (c) 2CS2(g)+3Cl2(g)CCl4(g)+S2Cl2(g)(T=125C) (d) 2SO2(g)+O2(g)2SO3(g)(T=675C) (e) CS2(g)CS2(l)(T=90C)Consider the following reaction at 298 K: N2O4(g)2NO2(g)KP=0.142 What is the standard free energy Change at this temperature? Describe what happens to the initial system. where the reactants and products are in standard states, as it approaches equilibrium.Determine the normal boiling point (in kelvin) of dichloroethane, CH2Cl2. Find the actual boiling point using the Internet or some other source, and calculate the percent error in the temperature. Explain the differences, if any, between the two values.Under what conditions is N2O3(g)NO(g)+NO2(g) spontaneous?At mom temperature, the equilibrium constant (Kw) for the self-ionization of water is 1.001014. Using this information, calculate the standard free energy change for the aqueous reaction of hydrogen ion with hydroxide ion to produce water. (Hint: The reaction is the reverse of the self-ionization reaction.)Hydrogen sulfide is a pollutant found in natural gas. Following its removal, it is convened to sulfur by the reaction 2H2S(g)+SO2(g)38S8(s,rhombic)+2H2O(l). What is the equilibrium constant for this reaction? Is the reaction endothermic or exothermic?Consider the decomposition of CaCO3(s) into CaO(s) and Co2(g). What is the equilibrium partial pressure of CO2 at room temperature?In the laboratory, hydrogen chloride (HCl(g)) and ammonia (NH3(g)) often escape from bottles of their solutions and react to form the ammonium chloride (NH4Cl(s)), the white glaze often seen on glassware. Assuming that the number of moles of each gas that escapes into the room is the same, what is the maximum partial pressure of HCl and NH3 in the laboratory at room temperature? (Hint: The partial pressures will be equal and are at their maximum value when at equilibrium.)Benzene can be prepared from acetylene. 3C2H2(g)C6H6(g). Determine the equilibrium constant at 25 C and at 850 C. Is the reaction spontaneous at either of these temperatures? Why is all acetylene not found as benzene?Carbon dioxide decomposes into CO and O2 at elevated temperatures. What is the equilibrium partial pressure of oxygen in a sample at 1000 C for which the initial pressure of CO2 was 1.15 atm?Carbon tetrachloride, an important industrial solvent, is prepared by the chlorination of methane at 850 K. CH4(g)+4Cl2(g)CCl4(g)+4HCl(g) What is the equilibrium constant for the reaction at 850 K? Would the reaction vessel need to be heated or cooled to keep the temperature of the reaction constant?Acetic acid, CH3CO2H, can form a dimer, (CH3CO2H)2, in the gas phase.. 2CH3CO2H(g)(CH3CO2H)2(g) The dimer is held together by to hydrogen bonds with a total strength of 66.5 kJ per mole of dimer. At 25 C, the equilibrium constant for the dimerization is 1.3103 (pressure in atm). What is ?S for the reaction?Nitric acid, HNO3, can be prepared by the following sequence of reactions: 4NH3(g)+5O2(g)4NO(g)+6H2O(g)2NO(g)+O2(g)2NO2(g)3NO2(g)+H2O(l)2HNO3(l)+NO(g) How much heat is evolved when 1 mol of NH3(g) is converted to HNO3(l)? Assume standard states at 25 C.Determine G for the following reactions. (a) Antimony pentachloride decomposes at 448 C. The reaction is: SbCl5(g)SbCl3(g)+Cl2(g) An equilibrium mixture in a 5.00 L flask at 448 C contains 3.85 g of SbCl5, 9.14 g of SbCl3, and 2.84 g of Cl2. (b) Chlorine molecules dissociate according to this reaction: Cl2(g)2Cl(g) 1.00% of Cl2 molecules dissociate at 975 K and a pressure of 1.00 atm.Given that the Gf for Pb2+(aq) and Cl-(aq) is -24.3 kJ/mole and -131.2 kJ/mole respectively, determine the solubility product, Ksp, for PbCl2(s).Determine the standard free energy change, Gf, for the formation of S2-(aq) given that the Gf for. Ag*(aq) and Ag2S(s) are 77.1 kJ/mole and 395 kJ/mole respectively, and the solubility product for Ag2S(s) is 81051.Determine the standard enthalpy change, entropy change, and free energy change for the conversion of diamond to graphite. Discuss the spontaneity of the conversion with respect to the enthalpy and entropy changes. Explain why diamond spontaneously changing into graphite is not observed.The evaporation of one mole of water at 298 K has a standard free allergy change of 8.58 kJ. H2O(l)H2O(g)G298=8.58kJ (a) Is the evaporation of water under standard thermodynamic conditions spontaneous?. (b) Determine the equilibrium constant, KP, for this physical process. (c) By calculating G, determine if the evaporation of water at 298 K is spontaneous when the partial pressure of water, PH2O, is 0.011 atm.. (d) If the evaporation of water were always nonspontaneous at room temperature, wet laundry would never dry when placed outside. In order for laundry to dry, what must be the value of PH2O in the air?In glycolysis, the reaction of glucose (Glu) to form glucose-6-phosphate (G6P) requires ATP to be present as described by the following equation: Glu+ATPG6P+ADPG298=17kJ In this process, ATP becomes ADP summarized by the following equation: ATPADPG298=30kJ Determine the standard free energy change for the following reaction, and explain why ATP is necessary to drive this process: GluG6PG298=?One of the important reactions in the biochemical pathway glycolysis is the reaction of glucose-6-phosphate (G6P) to form fructose-6-phosphate (F6P): G6PF6PG298=1.7kJ (a) Is the reaction spontaneous or nonspontaneous under standard thermodynamic conditions?. (b) Standard thermodynamic conditions imply the concentrations of G6P and F6P to be 1 M, however, in a typical cell, they are not even Close to these values. Calculate G when the concentrations of G6P and F6P are 120 M and 28 M respectively, and discuss the spontaneity of the forward reaction under these conditions. Assume the temperature is 37 C.Without doing a numerical calculation, determine which of the following will reduce the free energy change for the reaction, that is, make it less positive or more negative, when the temperature is increased. Explain. (a) N2(g)+3H2(g)2NH3(g) (b) HCl(g)+NH3(g)NH4Cl(s) (c) (NH4)2Cr2O7(s)Cr2O3(s)+4H2O(g)+N2(g) (d) 2Fe(s)+3O2(g)Fe2O3(s)When ammonium chloride is added to water and stirred, it dissolves spontaneously and the resulting solution feels cold. Without doing any calculations, deduce the signs of G, H, and S for this process, and justify your choices.An important source of copper is from the copper ore, chalcocite, a form of copper(I) sulfide. When heated, the Cu2S decomposes to form copper and sulfur described by the following equation: Cu2S(s)Cu(s)+S(s) (a) Determine G298 for the decomposition of Cu2S(s). (b) The reaction of sulfur with oxygen yields sulfur dioxide as the only product. Write an equation that describes this reaction, and determine G298 for the process. (c) The production of copper from chalcocite is performed by roasting the Cu2S in air to produce the Cu. By combining the equations from Parts (a) and (b), write the equation that describes the roasting of the chalcocite, and explain why coupling these reactions together makes for a more efficient process for the production of the copper.What happens to G (becomes more negative or more positive) for the following chemical reactions when the partial pressure of oxygen is increased? (a) S(s)+O2(g)SO2(g) (b) 2SO2(g)+O2(g)2SO3(g) (c) HgO(s)Hg(l)+O2(g)If a 2.5 A current is run through a circuit for 35 minutes, how many coulombs of charge moved through the circuit?For the scenario in the previous question, how many electrons moved through the circuit?For each of the following balanced half-reactions, determine whether an oxidation or reduction is occurring. (a) Fe3++3eFe (b) CrCr3++3e (c) MnO42MnO4+e (d) Li++eLi For each of the following balanced half-reactions, determine whether an oxidation or reduction is occurring. (a) Cl+3eCl2 (b) Mn2+MnO2 (c) H2H+ (d) NO3NO Given the following pairs of balanced half-reactions, determine the balanced reaction for each pair of half-reactions in an acidic solution. (a) CaCa2++2e,F2+2e2F (b) LiLi++e,Cl2+2e2Cl (c) FeFe3++3e,Br2+2e2Br (d) AgAg++e,MnO4+4H++3eMnO2+2H2O Balance the following in acidic solution: (a) H2O2+Sn2+H2O+Sn4+ (b) PbO2+HgHg22++Pb2+ (c) Al+Cr2O72Al3++Cr3+Identify the species that undergoes oxidation, the species that undergoes reduction, the oxidizing agent, and the reducing agent in each of the reactions of the previous problem.Balance the following in acidic solution: (a) SO32(aq)+Cu(OH)2(s)SO42(aq)+Cu(OH)(s) (b) O2+Mn(OH)2(s)MnO2(s) (c) NO3(aq)+H2(g)NO(g) (d) Al(s)+CrO42(aq)Al(OH)3(s)+Cr(OH)4(aq)Identify the species that was oxidized, the species that was reduced, the oxidizing agent, and the reducing agent in each of the reactions of the previous problem.Why is it not possible for hydroxide ion (OH-) to appear in either of the half-reactions or the overall equation when balancing oxidation—reduction reactions in acidic solution?Why is it not possible for hydrogen ion (H+) to appear in either of the half-reactions or the overall equation when balancing oxidationreduction reactions in basic solution?Why must the charge balance in oxidation-reduction reactions?Write the following balanced reactions using cell notation. Use platinum as an inert electrode, if needed.. (a) Mg(s)+Ni2+(aq)Mg2+(aq)+Ni(s) (b) 2Ag+(aq)+Cu(s)Cu2(aq)+2Ag(s) (c) Mn(s)+Sn(NO3)2(aq)Mn(NO3)2(aq)+Au(s) (d) 3CuNO3(aq)+Au(NO3)3(aq)3Cu(NO3)2(aq)+Au(s)Given the following cell notations, determine the species oxidized, species reduced, and the oxidizing agent and reducing agent, without writing the balanced reactions. (a) Mg(s)|Mg2+(aq)Cu2+(aq)|Cu(s) (b) Ni(s)|Ni2+(aq)Ag+(aq)|Ag(s)For the cell notations in the previous problem, write the corresponding balanced reactions.Balance the following reactions and write the reactions using cell notation. Ignore any inert electrodes, as they are never part of the half-reactions. (a) Al(s)+Zr4+(aq)Al3+(aq)+Zr(s) (b) Ag+(aq)+No(g)Ag(s)+NO3(aq) (acidic solution). (C) SiO32(aq)+Mg(s)Si(s)+Mg(OH)2(s) (basic solution). (d) CIO3(aq)+MnO2(s)CI(aq)+MnO4(aq) (basic solution)Identify the species oxidized species reduced, and the oxidizing agent and reducing agent for all the reactions in the previous problem.From the information provided, use cell notation to describe the following systems: (a) In one half-cell, a solution of Pt(NO3)2 forms Pt metal, while in the other half-Cell, Cu metal goes into a.Cu(NO3)2 solution with all solute concentrations 1 M. (b) The cathode consists of a gold electrode in a 0.55 M Au(NO3)3 solution and the anode is a magnesium electrode in 0.75 M Mg(NO3)2 solution. (c) One half-cell consists of a silver electrode in a 1 M AgNO3 solution, and in the other half-cell, a copper Electrode in 1 M Cu(NO3)2 is oxidized.Why is a salt bridge necessary in galvanic cells like the one in Figure 17.4?An active (metal) electrode was found to gain mass as the oxidation-reduction reaction was allowed to proceed. Was the electrode part of the anode or cathode? Explain.An active (metal) electrode was found to lose mass as the oxidation-reduction reaction was allowed to proceed. Was the electrode part of the anode or cathode? Explain.The mass of three different metal electrodes, each from a different galvanic cell, were determined before and after the current generated by the oxidation-reduction reaction in each cell was allowed to flow for a few minutes. The first metal electrode, given the label A, was found to have increased in mass; the second metal electrode, given the label B, did not change in mass; and the third metal electrode, given the label C, was found to have lost mass. Make an educated guess as to which electrodes were active and which were inert electrodes, and which were anode(s) and which were the cathode(s).For each reaction listed, determine its standard cell potential at 25 C and whether the reaction is spontaneous at standard conditions. (a) Mg(s)+Ni2+(aq)Mg2+(aq)+Ni(s) (b) 2Ag+(aq)+Cu(s)Cu2+(aq)+2Ag(s) (c) Mn(s)+Sn(NO3)2(aq)Mn(NO3)2(aq)+Sn(s) (d) 3Fe(NO3)2(aq)+Au(NO3)3(aq)3Fe(NO3)3(aq)+Au(s)For each reaction listed, determine its standard cell potential at 25 C and whether the reaction is spontaneous at standard conditions. (a) Mn(s)+Ni2+(aq)Mn2+(aq)+Ni(s) (b) 3Cu2+(aq)+2Al(s)2Al3+(aq)+3Cu(s) (c) Na(s)+LiNO3(aq)NaNO3(aq)+Li(s) (d) Ca(NO3)2(aq)+Ba(s)Ba(NO3)2(aq)+Ca(s)Determine the overall reaction and its standard cell potential at 25 C for this reaction. Is the reaction spontaneous at standard conditions? Cu(s)|Cu2+(aq)Au3+(aq)|Au(s)Determine the overall reaction and its standard cell potential at 25 C for the reaction involving the galvanic cell made from a half-cell consisting of a silver electrode in 1 M silver nitrate solution and a half-cell consisting of a zinc electrode in 1 M zinc nitrate. Is the reaction spontaneous at standard conditions?Determine the overall reaction and its standard cell potential at 25 C for the reaction involving the galvanic cell in which cadmium metal is oxidized to 1 M cadmium(II) ion and a half—cell consisting of an aluminum electrode in 1 M aluminum nitrate solution. 15 the reaction spontaneous at standard conditions?Determine the overall reaction and its standard cell potential at 25 C for these reactions. Is the reaction spontaneous at standard conditions? Assume the standard reduction for Br2(l) is the same as for Br2(aq).. Pt(s)|H2(g)|H+(aq)Br2(aq),Br(aq)|Pt(s)For the standard cell potentials given here, determine the ?G for the cell in k].. (a) 0.000V,n=2 (b) +0.434V,n=2 (c) -2.439 V, n = 1 For the ?G values given here, determine the standard cell potential for the cell.. (a) 12kJ/mol,n=3 (b) 45kJ/mol,n=1 Determine the standard cell potential and the cell potential under the stated conditions for the electrochemical reactions described here. State whether each is spontaneous or nonspontaueous under each set of conditions at 293.15 K. (a) Hg(l)+S2(aq,0.10M)+2Ag+(aq,0.25M)2Ag(s)+HgS(s) (b) The galvanic cell made from a half-cell consisting of an aluminum electrode in 0.015 M aluminum nitrate solution and a half—cell consisting of a nickel electrode in 025 M nickel(l) nitrate solution. (c) The cell made of a half-cell in which 1.0 M aqueous bromide is oxidized to 0.11 M bromine ion and a half-cell in which aluminum ion at 0.023 M is reduced to aluminum metal. Assume the standard reduction potential for Br2(l) is the same as that of Br2(aq).Determine G and G for each of the reactions in the previous problem.Use the data in Appendix L to determine the equilibrium constant for the following reactions. Assume 298.15 K if no temperature is given. (a) AgCl(s)Ag+(aq)+Cl(aq) (b) CdS(s)Cd2+(aq)+S2(aq) t 377 k (c) Hg2+(aq)+4Br(aq)[HgBr4]2(aq) (d) H2O(l)H+(aq)+OH(aq) at 25 C What are the desirable qualities of an electric battery?List some things that are typically considered when selecting a battery for a new application.Consider a battery made from one half-cell that consists of a capper electrode in 1 M CuSO4 solution and another half—cell that consists of a lead electrode in 1 M Pb(NO3)2 solution. (a) What are the reactions at the anode, cathode, and the overall reaction? (b) What is the standard cell potential for the battery? (c) Most devices designed to use dry-cell batteries can operate between 1.0 and 1.5 V. Could this tell he used to make a battery that could replace a dry-cell battery? Why or why not. (d) Suppose sulfuric acid is added to the half—cell with the lead electrode and some PbSO4(s) forms. Would the cell potential increase, decrease, or remain the same?Consider a battery with the overall reaction: Cu(s)+2Ag+(aq)2Ag(s)+Cu2+(aq). (a) What is the reaction at the anode and cathode?. (b) A battery is dead" when it has no cell potential. What is the value of Q when this battery is dead?. (c) If a particular dead battery was found to have [Cu2+]=0.11M, what was the concentration of silver ion?An inventor proposes using a SHE (standard hydrogen electrode) in a new battery for smartphones that also removes toxic carbon monoxide from the air: Anode:CO(g)+H2O(l)CO2(g)+2H+(aq)+2eEanode=0.53VCathode:2H+(aq)+2eH2(g)Ecathode=0V_Overall:CO(g)+H2O(l)CO2(g)+H2(g)Ecell=+0.53V Would this make a good battery for smartphones? Why or why not?Why do batteries go dead, but fuel cells do not?Explain what happens to battery voltage as a battery is used, in terms of the Nernst equation.Using the information thus far in this chapter, explain why battery-powered electronics perform poorly in low temperatures.Which member of each pair of metals is more likely to corrode (oxidize)? (a) Mg or Ca (b) Au or Hg (c) Fe or Zn (d) Ag or Pt Consider the following metals: Ag, Au, Mg, Ni, and Zn. Which of these metals could be used as a sacri?cial anode in the cathodic protection of an underground steel storage tank? Steel is mostly iron, 50 use -0.447 V as the standard reduction potential for steel.Aluminum (E Al 3+/Al=2.07V) is more easily oxidized than iron (E Fe 3+/Fe=2.07V), and yet when both are exposed to the environment, untreated aluminum has very good corrosion resistance while the corrosion resistance of untreated iron is poor. Explain this observation.If a sample of iron and a sample of zinc come into contact, the zinc corrodes but the iron does not. If a sample of iron comes into contact with a sample of copper, the iron corrodes but the copper does not. Explain this phenomenon.Suppose you have three different metals. A, B, and C. When metals A and B come into contact. B confides and A does not corrode. When metals A and C come into contact, A corrodes and C does not corrode. Based on this information, which metal corrodes and which metal does not corrode when B and C come into contact?Why would a sacrificial anode made of lithium metal be a bad choice despite its ELi+/Li=2.07V, which appears to be able to protect all the other metals listed in the standard reduction potential table?Identify the reaction at the anode, reaction at the cathode, the overall reaction, and the approximate potential required for the electrolysis of the following molten salts. Assume standard states and that the standard reduction potentials in Appendix L are the same as those at each of the melting points. Assume the efficiency is 100%. (a) CaCl2. (b) LiH. (c) AlCl3. (d) CrBr3 What mass of each product is produced in each of the electrolytic cells of the previous problem if a total charge of 3.33105 C passes through each cell? Assume the voltage is sufficient to perform the reduction.How long would it take to reduce 1 mole of each of the following ions using the current indicated? Assume the voltage is sufficient to perform the reduction. (a) AR3+, 1.234 A. (b) Ca2+, 22.2 A. (c) Cr5+, 37.45 A. (d) Au3+, 3.57 A A current of 2.345 A passes through the cell shown in Figure 17.20 for 45 minutes. What is the volume of the hydrogen collected at room temperature if the pressure is exactly 1 atm? Assume the voltage is sufficient to perform the reduction. (Hint: 15 hydrogen the only gas present above the water?)An irregularly shaped metal part made from a particular alloy was galvanized with zinc using a Zn(NO3)2 solution. When a current of 2.599 A was used, it took exactly 1 hour to deposit a 0.01123-mm layer of zinc on the part. What was the total surface area of the part? The density of zinc is 7.140 g/cm3. Assume the efficiency is 100%.How do alkali metals differ from alkaline each metals in atomic structure and general properties?Why does the reactivity of the alkali metals decrease from cesium to lithium?Predict the formulas for the nine compounds that may form when each species in column 1 of Table 18.3 reacts with each species in column 2. 1 2 Na l Sr Se Al O Predict the best choice in each of the following. You may wish to review the Chapter on electronic structure for relevant examples. (a) the most metallic 0f the elements Al, Be, and Ba. (b) the most covalent of the compounds NaCl, CaCl2, and BeCl2;. (c) the lowest first ionization energy among the elements Rb, K, and Li. (d) the smallest among Al, Al+, and Al3+. (e) the largest among Cs+, Bar2+, and Xe Sodium chloride and strontium chloride are both white solids. How could you distinguish one from the other?The reaction of quicklime, CaO, with water produces slaked lime, Ca(OH)2, which is widely used in the construction industry to make mortar and plaster. The reaction of quicklime and water is highly exothermic: CaO(s)+H2O(l)Ca(OH)2(s)H=350kJmol1 (a) What is the enthalpy of reaction per gram of quicklime that reacts?. (b) How much heat, in kilojoules, is associated with the production of 1 ton of slaked lime?

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