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Chem 142 Exam 3/ CHM 142 Exam 3 Review
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Differential rate law - correctly answered Rate = k[A]^m[B]^n When do you use differential rate law? - correctly answered rate vs concentration When do you use integrated rate law? - correctly answered concentration vs time Zero order rate law - correctly answered [A]t=-kt+[A] First order rate law - correctly answered ln[A]t=-kt+ln[A] Second order rate law - correctly answered 1/[A]t=kt+1/[A] Zero order slope - correctly answered -k First order slope - correctly answered -k Second order slope - correctly answered k Zero order half life - correctly answered t1/2 = [A]0 / 2k First order half life - correctly answered t1/2 = ln2/k Second order half life - correctly answered t1/2 = 1/k[A]
pressure and volume relationship - correctly answered inverse, P1V1=P2V volume and temperature relationship - correctly answered direct, V1/T1=P2/V pressure and temperature relationship - correctly answered direct, P1/T1=P2/T Ideal Gas Law - correctly answered PV=nRT PxMW=dRT Kinetic energy - correctly answered KE=1/2mv^ 1 J - correctly answered 1 kg m^2/s^ root mean square velocity - correctly answered Urms = square root of 3RT/M rate of effusion - correctly answered rate A/ rate B = √molecular mass B/ √molecular mass A Gases behave ideally at - correctly answered high temperature (298K) and low pressure (1atm) KE avg in one mole of gas - correctly answered KE = 3/2 RT u(rms) - correctly answered the speed of a molecule with the average kinetic energy u(m) - correctly answered most probable speed u(avg) - correctly answered average speed Given the pKa's of several polyprotic acids choose the strongest acid among the ions given below.
Calculate the pH of a 3.72 x 10-2 M solution of ammonia, NH3 (Kb=1.8 x 10-5). - correcty answered
The acid ionization constant (Ka) for HI is estimated to be 1 x 109. What is the value of Kb for I-? - correcty answered 1 x 10^- An aqueous solution of NH4Cl will be acidic, because of the hydrolysis of NH4+ ions. basic, because of the hydrolysis of Cl- ions. basic, because of the ionization of NH3. basic, because of the hydrolysis of NH4+ ions. acidic, because of the hydrolysis of Cl- ions. - correcty answered acidic, because of the hydrolysis of NH4+ ions. Which of the following salts will form basic solution(s) in water? NaBr,, NaF, NaNO3, Na3PO4, Na2SO3 - correcty answered NaF, Na3PO4 and Na2SO Which of the following salts will form acidic solution(s) in water? CrCl3, K2CO3, KI, NH4NO3, SrS - correcty answered CrCl3 and NH4NO Given the pKa's of several triprotic and diprotic acids choose the strongest base among the ions given below. H3AsO4: pKa1 = 2.26, pKa2 = 6.77, pKa3 = 11. H3PO4: pKa1 = 2.12, pKa2 = 7.21, pKa3 = 12. H2SO3: pKa1 = 1.77, pKa2 = 7. H2CO3: pKa1 = 6.37, pKa2 = 10. H2SeO3: pKa1 = 2.64, pKa2 = 8.
H2PO4- HSO3- H2AsO4-
HSeO3- HCO3- - correcty answered HCO3- Calculate the pH of a 0.364 M aqueous solution of sodium acetate (CH3COONa). For CH3COOH, Ka = 1, x 10-5. - correcty answered 9. Using the pKa's of five weak acids choose the salt of one of them that will have the highest pH if solutions of the same concentration were compared. HBrO: pKa = 8. HClO: pKa = 7. HIO: pKa = 10. HF: pKa = 3. HCN: pKa = 9. NaCN NaF NaIO NaBrO NqClO - correcty answered NaIO Which of the following is the weakest acid? HBrO HClO HClO HBrO HClO2 - correcty answered HBrO Arrange the following acids: HBrO, HIO, and HI in order of increasing strength (weakest to strongest). - correcty answered HIO < HBrO < HI
C2H5NH2(aq) + H3O+(aq) → C2H5NH3+(aq) + H2O(l) C2H5NH3+(aq) + OH-(aq) → C2H5NH2(aq) + H2O(l) - correcty answered C2H5NH3+(aq) + OH-(aq) → C2H5NH2(aq) + H2O(l) Given the Kb's of three weak bases and the Ka's of two weak acids choose the one that could be used as one of the components of a buffer solution with a pH of 6.35. CH3COOH (Ka = 1.8 x 10-5) CH3NH2 (Kb = 4.4 x 10-4) NH2OH (Kb = 1.1 x 10-8) HCOOH (Ka = 1.8 x 10-4) C5H5N (Kb = 1.7 x 10-9) - correcty answered NH2OH (Kb = 1.1 x 10-8) Which one of the following pairs of aqueous solutions will not produce a buffer solution regardless of proportions in which they are mixed together? RbOH, HNO CH3COOH, KOH K2SO3, NaHSO (CH3)2NH, (CH3)2NH2Br C2H5NH2, HCl - correcty answered RbOH, HNO A buffer solution could be formed when a solution of methylamine, CH3NH2, is mixed with a solution of KOH. HI. NaCl. CH3OH. (CH3)2NH. - correcty answered HI The acid ionization constants for several acids are given below: H3PO4 Ka1: 7.5 x 10-3 Ka2: 6.2 x 10-8 Ka3: 4.2 x 10- H2CO3 Ka1: 4.3 x 10-7 Ka2: 5.6 x 10-
HNO2 Ka1: 4.5 x 10- CH3COOH Ka1: 1.8 x 10- Which of the following aqueous solutions should be mixed to prepare a buffer solution with a pH of 7.70? Correct! NaH2PO4 and Na2HPO H2CO3 and NaHCO H3PO4 and NaH2PO HNO2 and NaNO CH3COOH and CH3COONa - correcty answered NaH2PO4 and Na2HPO Which of the following buffer solutions containing CH3COONa and CH3COOH would have a pH of 4.88? Ka for CH3COOH is 1.8 x 10-5. 0.055 M CH3COONa and 0.015 M CH3COOH 0.015 M CH3COONa and 0.055 M CH3COOH 0.055 M CH3COONa and 0.055 M CH3COOH 0.075 M CH3COONa and 0.055 M CH3COOH 0.015 M CH3COONa and 0.075 M CH3COOH - correcty answered 0.075 M CH3COONa and 0.055 M CH3COOH Instructions for making up a buffer solution say to mix 90.0 mL of a 0.125 M solution of acetic acid, CH3COOH, with 20.0 mL of a 0.175 M solution of sodium acetate, CH3COONa. What is the pH of this solution? Ka for acetic acid is 1.8 x 10-5. - correcty answered 4. What is the pH of the buffer solution which contains 0.50 M ammonia (NH3) and 0.25 M ammonium chloride (NH4Cl) after the addition of 20.0 mL of a 0.20 M solution of HCl to 80.0 mL of the buffer? The pKb for ammonia is equal to 4.74. - correcty answered 9. The values of pKa's for H3AsO4 are pKa1=2.19, pKa2=6.94, and pKa3=11.50. Use the appropriate pKa to find the value of pKb for HAsO42-. - correcty answered 7. Consider 0.010 M aqueous solutions of five weak bases. Which solution will have the highest pH? NH3 (Kb = 1.8 x 10-5)
Which one of the following is the strongest base? BrO3- BrO- ClO2- ClO- ClO3- - correcty answered BrO- In the reaction MgO(s) + SO2(g) → MgSO3(s) SO2 acts as - correcty answered Lewis acid Addition of a small amount of an aqueous solution of sodium hydroxide to an aqueous solution of ammonia will - correcty answered increase the pH but will not affect Kb of ammonia. Which of the following would cause the percent ionization of HNO2 to decrease? A: addition of NaCl B: addition of NaNO C: addition of HCl D: diluting with more water - correcty answered B and C Calculate the concentration of (CH3)3NH+ ions in a 5.0 x 10-2 M solution of trimethylamine, (CH3)3N, that is also 6.0 x 10-2 M in NaOH. Kb for trimethylamine is 6.4 x 10-5 - correcty answered 5.3 x 10-5 M Given the pKa's of three acids and pKb's of two bases, choose the one that could be used as one of the components of a buffer solution with a pH of 10.75. ClCH2COOH (pKa = 2.85) CH3NH2 (pKb = 3.36) NH3 (pKb = 4.75) HCOOH (pKa = 3.77) CH3COOH (pKa = 4.75) - correcty answered CH3NH2 (pKb = 3.36)
Which of the following pairs of aqueous solutions when mixed together will form a buffer solution? NH4Cl, NaCl CH3COOH, HClO CH3NH2, KOH K2SO3, NaHSO CH3NH2, CH3COONa - correcty answered K2SO3, NaHSO What is the net ionic equation for the reaction that occurs when a small amount of hydrochloric acid is added to the (C2H5)2NH/ (C2H5)2NH2Cl buffer solution? (C2H5)2NH2+(aq) + H2O(l) → (C2H5)2NH(aq) + H3O+(aq) (C2H5)2NH(aq) + H3O(aq) → (C2H5)2NH2(aq) + H2O(l) (C2H5)2NH2+(aq) + OH-(aq) → (C2H5)2NH(aq) + H2O(l) (C2H5)2NH(aq) + H3O+(aq) → (C2H5)2NH2+(aq) + H2O(l) (C2H5)2NH(aq) + H2O(l) → (C2H5)2NH2+(aq) + OH-(aq) - correcty answered (C2H5)2NH(aq) + H3O+(aq) → (C2H5)2NH2+(aq) + H2O(l) Calculate the pH of a buffer solution which contains 0.161 M formic acid (HCOOH) and 0.316 M sodium formate (HCOONa). The Ka for formic acid is equal to 1.8 x 10-4. - correcty answered 4. Instructions for making up a buffer solution say to mix 18.3 mL of a 0.121 M solution of benzoic acid, HC7H5O2, with 37.4 mL of a 0.171 M solution of sodium benzoate,NaC7H5O2. What is the pH of this solution? For benzoic acid, pKa = 4.20. - correcty answered 4. A buffer solution contains 0.215 M NH3 and 0.253 M NH4Cl. What is the pH of the buffer solution after the addition of 30.9 mL of 0.125 M NaOH to 58.3 mL of the buffer? For NH3, pKb = 4.74. - correcty answered 9. A 20.0 mL sample of a 0.224 M solution of NaOH is titrated with a 0.187 M solution of HCl. Calculate the pH after the addition of 20.1 mL of HCl solution. - correcty answered 12.
HIO2 ( aq) HClO (aq) HIO (aq) - correcty answered HClO2 (aq) n the following reaction Fe 3+(aq) + 6CN-(aq) -> Fe(CN)6 3-(aq) CN- acts as - correcty answered Lewis base What is the net ionic equation for the reaction that occurs when a small amount of sodium hydroxide is added to the CH3COOH/CH3COONa buffer solution? CH3COOH(aq) + OH-(aq) -> CH3COO-(aq) + H2O(l) CH3COO-(aq) + OH-(l)-> CH2COO 2-(aq) + H2O(l) Ch3COOH(aq) + OH(aq) -> CH3COO(aq) + H2O(l) CH3COOH(aq) + 2OH-(aq) -> CH2COO 2-(aq) + 2H2O(l) CH3COO-(aq) + H2O(l) -> CH3COOH(aq) + OH-(aq) - correcty answered CH3COOH(aq) + OH-(aq) -> CH3COO-(aq) + H2O(l) Which of the following buffer solutions containing HCOOH and HCOONa would have a pH of 3.88? Ka for HCOOH is 1.8E-4. 0.015 M HCOOH and 0.055 M HCOONa 0.055 M HCOOH and 0.055 M HCOONa 0.055 M HCOOH and 0.015 M HCOONa 0.055 M HCOOH and 0.075 M HCOONa 0.015 M HCOOH and 0.075 M HCOONa - correcty answered 0.055 M HCOOH and 0.075 M HCOONa Calculate the pH of a buffer solution which contains 0.206 M propionic acid (HC3H5O2) and 0.341 M sodium propionate (NaC3H5O2). The Ka for propionic acid is equal to 1.3*10-5. - correcty answered
Which of the following solutions if titrated with 0.100 M NaOH would have the pH at the equivalence equal to 7.0?
KNO
NH4Cl NH HNO CH3COOH - correcty answered HNO 20.0 mL sample of a 0.224 M solution of HCl is titrated with a 0.187 M solution of NaOH. Calculate the pH after the addition of 23.2 mL of NaOH solution - correcty answered 2. Instructions for making up a buffer solution say to mix 90.0 mL of a 0.125 M solution of formic acid, HCOOH, with a 20.0 mL of a 0.175 M solution of sodium formate, HCOONa. What is the pH of this solution? Ka for formic acid is 1.710-4. - correcty answered 3. A 20.0 mL sample of 0.687 M HBr is titrated with a 0.216 M NaOH solution. The pH after the addition of 10.0 mL of NaOH is _____. - correcty answered 0. What is the pH of the buffer solution which contains 0.250 M acetic acid (CH3COOH) and 0.500 M sodium acetate (CH3COONa) after the addition of 20.0 mL of a 0.200 M solution of HCl to 80.0 mL of the buffer? Ka for CH3COOH is equal to 1.810-5. - correcty answered 4. Calculate the pH of a 0.260 M aqueous solution of KNO2. For HNO2, Ka = 4.5*10-4. - correcty answered
Given the pKa's of H3AsO4, H2SO3, and H2CO3 arrange the following three ions in order of increasing strength (from weakest to the strongest): H2AsO4-, HSO3-, HCO3-. - correcty answered HCO3-< HSO3- < H2AsO4- Which of the following species cannot act as a Lewis acid? BF F- H+ CO
PbCl2(s) + Cl- → PbCl3-(aq) Fe(s) + 5CO(g) → Fe(CO)5(l) The two species that act as Lewis acids are - correcty answered PbCl2 and Fe Arrange the following acids:HClO, HBrO, and HBr In order of increasing strength (weakest to strongest). - correcty answered HBrO < HClO < HBr Calculate the pH of a 6.27x10-3 M solution of pyridine (C5H5N). Kb = 1.7x10-9. - correcty answered
0.0131 - correctly answered In a 0.731M solution, a weak acid is 12.5% dissociated. Calculate Ka 0.02418, 0.024, 4.1x10^-13 - correctly answered HF has a Ka of 6.8 x 10^-4. What are [H2O+], [F-] and [OH-]? 11.97 - correctly answered What is the pH of 0.11M diethylamine where its Kb is 8.6x10^-4? 9.1 x 10^-7 - correctly answered determine the Kb of a weak base of 0.23M solution if the base has a pH of 10.66 at 25 C 1.59 x 10^-10 - correctly answered what is the Kb of the benzoate ion? 3.1 x 10^-10 - correctly answered what is the Kb of the 2-hydroxylammonium ion (pKb = 4.49) 5.76 - correctly answered what is the pH of 0.135M methylammonium bromide, Kb = 4.4x10^- 8.38 - correctly answered what is the pH of 0.40M NaF acidic - correctly answered is Cr(NO3)3 acidic, basic or neutral?
basic - correctly answered is NaHS acidic, basic or neutral? acidic - correctly answered is Zn(CH3COO)2 acidic, basic or neutral? Co is the base, Ni is the acid - correctly answered what are the lewis acid and lewis base in the equation 4CO + Ni --> Ni(CO) KCN/HCN, Na2SO4/NaHSO4 - correctly answered What solution can act as a buffer solution? KCN/HCN Na2SO4/NaHSO NH3/NH4NO NaI/HI 10.4 - correctly answered Find the pH of a buffer than consists of 0.34M CH3NH2 and 0.58M CH3NH3Cl (pKb of CH3NH2 = 3.35) Ka2, 7.5 - correctly answered A buffer consists of 0.16M NaH2PO4 and 0.32M Na2HPO4. Phosphoric acid is a triprotic acid (Ka1 = 7.2 x 10^-3, Ka2 = 6.3 x 10^-8, Ka3 = 4.2 x 1-^-13). Which buffer is most important? What is the buffer pH? 4.3 - correctly answered what is the correct concentration ratio of [CH3COO-]/[CH3COOH] of a buffer solution that has a pH of 5.37 (Ka = 1.8 x 10^-5) 9.18 - correctly answered A buffer that contains a 0.491M base, B, and 0.297M of its conjugate acid, BH+, has a pH of 9.14. What is the pH after 0.00200mol HCl is added to 0.250L of solution 10.20 - correctly answered A buffer is prepared by mixing 50.0mL of 0.050M sodium bicarbonate and 10.7ml of 0.10M NaOH (Ka = 4.7 x 10^-11) 12.79, 10.90, 1.928 - correctly answered calculate the pH during the titration of 30.00ml of 0.1000M KOH and 0.1000M HBR solution after the following additions of acid:
CH3NH2 (Kb = 4.4 x 10-4) (CH3)3N (Kb = 7.4 x 10-5) HONH2 (Kb = 1.1 x 10-8) NaNO2 - correctly answered Which of the following salts will form a basic solution in water? NH4Cl NaNO NaNO NaBr NaCl NaNO2/HNO2 (Ka = 4.5 x 10-4) - correctly answered Which one of the following mixtures is suitable for making a buffer solution with an optimum pH of 3.20-3.40? NaOCl/HOCl (Ka = 3.2 x 10-8) CH3COONa/CH3COOH (Ka = 1.8 x 10-5) NaCl/HCl NH3/NH4Cl (Ka(NH4+) = 5.6 x 10-10 NaNO2/HNO2 (Ka = 4.5 x 10-4) HPO42-(aq) + H3O+(aq) → H2PO4-(aq) + H2O(l) - correctly answered What is the net ionic equation for the reaction that occurs when a small amount of hydrochloric acid is added to the Na2HPO4/NaH2PO buffer solution? HCO3-(aq) + OH-(aq) → CO32-(aq) + H2O(l) - correctly answered What is the net ionic equation for the reaction that occurs when a small amount of potassium hydroxide is added to the K2CO3/KHCO3 buffer solution? HI - correctly answered A buffer solution could be formed when a solution of sodium acetate, (CH3)2COONa, is mixed with a solution of NH KOH. HI.
CH3OH.
NaCl. 9.44 - correctly answered Instructions for making up a buffer solution say to mix 75.0 mL of a 0.125 M solution of ammonia, NH3, with 35.0 mL of a 0.175 M solution of ammonium chloride, NH4Cl. What is the pH of this solution? pKb of ammonia is 4.74. 4.92 - correctly answered A buffer solution contains 0.200 M CH3COOH and 0.250 M CH3COONa. What is the pH of the buffer solution after the addition of 10.0 mL of 0.100 M NaOH to 50.0 mL of the buffer? Ka for CH3COOH is equal to 1.8 x 10-5. CH3NH2(aq) + HBr(aq) - correctly answered Which of the following titrations will result in a noticeably acidic solution at the equivalence point? HNO3(aq) + KOH(aq) CH3NH2(aq) + HBr(aq) HClO2(aq) + NaOH(aq) CH3COOH(aq) + LiOH(aq) KOH(aq) + HCl(aq) bromocresol green (Ka = 2.0 x 10-5) - correctly answered Which of the following indicators is suitable for the titration of 0.10 M NH3 (Kb = 1.8 x 10-5) with 0.15 M HCl? thymol blue (Ka = 6.3 x 10-10) phenolpthalein (Ka = 4.0 x 10-10) cresol red (Ka = 3.5 x 10-9) bromocresol green (Ka = 2.0 x 10-5) bromothymol blue (Ka = 1.0 x 10-7) 11.70 - correctly answered A 20.0 mL sample of a 2.00 x 10-2 M solution of nitrous acid, HNO2, is titrated with a 3.00 x 10-2 M solution of NaOH? What is the pH after 20.0 mL of NaOH solution have been added? Ka for HNO2 equals 4.5 x 10-4.
