Question 1

Which of the following solutions represents a good buffer system?

Accepted Answer

A) a solution that is 0.10 mol L-1 CH3COOH and 0.10 mol L-1 CH3COOLi 
B) a solution that is 0.10 mol L-1 HF and 0.10 mol L-1 CH3COONa 
C) a solution that is 0.10 mol L-1 HCl and 0.10 mol L-1 NH4+ 
D) a solution that is 0.10 mol L-1 NaOH and 0.10 mol L-1 KOH 
E) a solution that is 0.10 mol L-1 HCl and 0.10 mol L-1 KCl 
A) a solution that is 0.10 mol L-1 CH3COOH and 0.10 mol L-1 CH3COOLi 
B) a solution that is 0.10 mol L-1 HF and 0.10 mol L-1 CH3COONa 
C) a solution that is 0.10 mol L-1 HCl and 0.10 mol L-1 NH4+ 
D) a solution that is 0.10 mol L-1 NaOH and 0.10 mol L-1 KOH 
E) a solution that is 0.10 mol L-1 HCl and 0.10 mol L-1 KCl

Question 2

If the pKa of HCOOH is 3.74 and the pH of an HCOOH/HCOONa buffer solution is 3.89,which of the following is TRUE?

Accepted Answer

A) [HCOOH] [HCOONa] D) [HCOOH] >> [HCOONa] E) [HCOOH] << [HCOONa] A) [HCOOH] [HCOONa] D) [HCOOH] >> [HCOONa] E) [HCOOH] << [HCOONa]

Question 3

Calculate the pH of a buffer that is 0.225 mol L-1 CH3COOH and 0.162 mol L-1 CH3COOK.The Ka for CH3COOH is 1.8 × 10-5.

Accepted Answer

A) 4.89 
B) 9.11 
C) 4.74 
D) 9.26 
E) 4.60 
A) 4.89 
B) 9.11 
C) 4.74 
D) 9.26 
E) 4.60

Question 4

In which of the following solutions would solid PbBr2 be expected to be the least soluble at 25 °C?

Accepted Answer

A) 0.1 mol L-1 HBr 
B) 0.1 mol L-1 NaBr 
C) 0.1 mol L-1 CaBr2 
D) 0.1 mol L-1 K NO3 
A) 0.1 mol L-1 HBr 
B) 0.1 mol L-1 NaBr 
C) 0.1 mol L-1 CaBr2 
D) 0.1 mol L-1 K NO3

Question 5

Identify the indicator that can be used at the highest pH.

Accepted Answer

A) alizarin 
B) thymol blue 
C) crystal violet 
D) phenolphthalein 
E) alizarin yellow R 
A) alizarin 
B) thymol blue 
C) crystal violet 
D) phenolphthalein 
E) alizarin yellow R

Question 6

A sample contains Ba3(PO4)2, CdS,AgCl,NH4Cl,and ZnS.Identify the precipitate formed after the addition of 6 mol L-1 HCl,followed by the addition of H2S and 0.2 mol L-1 HCl,and subsequently the addition of OH- to a pH of 8.

Accepted Answer

A) Ba3(PO4)2 
B) CdS 
C) AgCl 
D) NH4Cl 
E) ZnS 
A) Ba3(PO4)2 
B) CdS 
C) AgCl 
D) NH4Cl 
E) ZnS

Question 7

A solution is prepared by dissolving 0.23 mol of formic acid and 0.27 mol of sodium formate in water sufficient to yield 1.00 L of solution.The addition of 0.05 mol of NaOH to this buffer solution causes the pH to increase slightly.The pH does not increase drastically because the NaOH reacts with the ________ present in the buffer solution.The $ K_{a} $ of formic acid is 1.8 × 10-4.

Accepted Answer

A)  $ \mathrm{H}_{2}O $ 
B)  $ \mathrm{H}_{3} \mathrm{O}^{+} $ 
C) formate 
D) formic acid 
E) This is a buffer solution: the pH does not change upon addition of acid or base. 
A)  $ \mathrm{H}_{2}O $ 
B)  $ \mathrm{H}_{3} \mathrm{O}^{+} $ 
C) formate 
D) formic acid 
E) This is a buffer solution: the pH does not change upon addition of acid or base.

Question 8

A 1.0 L buffer solution is 0.250 mol L-1 CH3COOH and 0.050 mol L-1 CH3COOLi.Which of the following actions will exceed the capacity of the buffer?

Accepted Answer

A) adding 0.050 moles of CH3COOLi 
B) adding 0.050 moles of CH3COOH 
C) adding 0.050 moles of HCl 
D) adding 0.050 moles of NaCl 
E) adding 0.050 moles of NH4Cl 
A) adding 0.050 moles of CH3COOLi 
B) adding 0.050 moles of CH3COOH 
C) adding 0.050 moles of HCl 
D) adding 0.050 moles of NaCl 
E) adding 0.050 moles of NH4Cl

Question 9

A 100.0 mL sample of 0.10 mol L-1 NH3 is titrated with 0.10 mol L-1 HNO3.Determine the pH of the solution after the addition of 100.0 mL of HNO3.The Kb of NH3 is 1.8 × 10-5.

Accepted Answer

A) 6.58 
B) 10.56 
C) 8.72 
D) 3.44 
E) 5.28 
A) 6.58 
B) 10.56 
C) 8.72 
D) 3.44 
E) 5.28

Question 10

A 100.0 mL sample of 0.10 mol L-1 NH3 is titrated with 0.10 mol L-1 HNO3.Determine the pH of the solution after the addition of 50.0 mL of HNO3.The Kb of NH3 is 1.8 × 10-5.

Accepted Answer

A) 4.74 
B) 7.78 
C) 7.05 
D) 9.26 
E) 10.34 
A) 4.74 
B) 7.78 
C) 7.05 
D) 9.26 
E) 10.34

Question 11

Which of the following is TRUE?

Accepted Answer

A) An effective buffer has a [base]/[acid] ratio in the range of 10 - 100. 
B) A buffer is most resistant to pH change when [acid] = [conjugate base]. 
C) An effective buffer has very small absolute concentrations of acid and conjugate base. 
D) The capacity of a buffer cannot be exceeded by adding too much strong base.It can only be exceeded by adding too much strong acid. 
E) A buffer has the best resistance to pH change when the buffer's pH is significantly lower than the pKa of the acid used to make the buffer solution. 
A) An effective buffer has a [base]/[acid] ratio in the range of 10 - 100. 
B) A buffer is most resistant to pH change when [acid] = [conjugate base]. 
C) An effective buffer has very small absolute concentrations of acid and conjugate base. 
D) The capacity of a buffer cannot be exceeded by adding too much strong base.It can only be exceeded by adding too much strong acid. 
E) A buffer has the best resistance to pH change when the buffer's pH is significantly lower than the pKa of the acid used to make the buffer solution.

Question 12

Determine the molar solubility of BaF2 in pure water.Ksp for BaF2 = 2.45 × 10-5.

Accepted Answer

A) 1.83 × 10-2 mol L-1 
B) 1.23 × 10-5 mol L-1 
C) 2.90 × 10-2 mol L-1 
D) 4.95 × 10-3 mol L-1 
E) 6.13 × 10-6 mol L-1 
A) 1.83 × 10-2 mol L-1 
B) 1.23 × 10-5 mol L-1 
C) 2.90 × 10-2 mol L-1 
D) 4.95 × 10-3 mol L-1 
E) 6.13 × 10-6 mol L-1

Question 13

Calculate the molar solubility of thallium chloride (TlCl)in 0.50 mol L-1 NaCl at 25 °C.Ksp for TlCl is $1.7 \times 10 ^{- 4}$

Accepted Answer

A) 8.5 × 10-5 mol L-1 
B) 3.4 × 10-4 mol L-1 
C) 9.2 × 10-3 mol L-1 
D) 1.3 × 10-2 mol L-1 
A) 8.5 × 10-5 mol L-1 
B) 3.4 × 10-4 mol L-1 
C) 9.2 × 10-3 mol L-1 
D) 1.3 × 10-2 mol L-1

Question 14

If the pKa of HCOOH is 3.74 and the pH of an HCOOH/HCOONa solution is 3.11,which of the following is TRUE?

Accepted Answer

A) [HCOOH]  [HCOONa] 
E) [HCOOH] >> [HCOONa] 
A) [HCOOH]  [HCOONa] 
E) [HCOOH] >> [HCOONa]

Question 15

When titrating a strong monoprotic acid with KOH at 25 °C,the

Accepted Answer

A) pH will be less than 7 at the equivalence point. 
B) pH will be greater than 7 at the equivalence point. 
C) titration will require more moles of base than acid to reach the equivalence point. 
D) pH will be equal to 7 at the equivalence point. 
E) titration will require more moles of acid than base to reach the equivalence point. 
A) pH will be less than 7 at the equivalence point. 
B) pH will be greater than 7 at the equivalence point. 
C) titration will require more moles of base than acid to reach the equivalence point. 
D) pH will be equal to 7 at the equivalence point. 
E) titration will require more moles of acid than base to reach the equivalence point.

Question 16

Explain the common ion effect with respect to molar solubility.

Accepted Answer

The common ion effect occurs when a solu

Question 17

What is the pH of a solution made by mixing 10.00 mL of 0.10 mol L-1 acetic acid with 10.00 mL of 0.10 mol L-1 KOH? Assume that the volumes of the solutions are additive.Ka = $1.8 \times 10^{ - 5}$ for CH3COOH.

Accepted Answer

A) 5.28 
B) 7.00 
C) 8.72 
D) 10.02 
A) 5.28 
B) 7.00 
C) 8.72 
D) 10.02

Question 18

What is the pH of a solution prepared by mixing 50.00 mL of 0.10 mol L-1 methylamine,CH3NH2,with 20.00 mL of 0.10 mol L-1 methylammonium chloride,CH3NH3Cl? Assume that the volume of the solutions are additive and that Kb = 3.70 × 10-4 for methylamine.

Accepted Answer

A) 10.17 
B) 10.57 
C) 10.97 
D) 11.78 
A) 10.17 
B) 10.57 
C) 10.97 
D) 11.78

Question 19

Give the name of the compound that is in antifreeze and is toxic to pets.

Accepted Answer

Ethylene g

Question 20

A 25.0 mL sample of 0.150 mol L-1 butanoic acid is titrated with a 0.150 mol L-1 NaOH solution.What is the pH after 13.3 mL of base is added? The $K _ { a }$ of butanoic acid is 1.5 × 10-5.

Accepted Answer

A) 1.34 
B) 4.55 
C) 3.08 
D) 4.77 
E) 4.88 
A) 1.34 
B) 4.55 
C) 3.08 
D) 4.77 
E) 4.88

Exam 16: Aqueous Ionic Equilibrium

Which of the following solutions represents a good buffer system?

If the pKa of HCOOH is 3.74 and the pH of an HCOOH/HCOONa buffer solution is 3.89,which of the following is TRUE?

Calculate the pH of a buffer that is 0.225 mol L-1 CH3COOH and 0.162 mol L-1 CH3COOK.The Ka for CH3COOH is 1.8 × 10-5.

In which of the following solutions would solid PbBr2 be expected to be the least soluble at 25 °C?

Identify the indicator that can be used at the highest pH.

A sample contains Ba3(PO4)2, CdS,AgCl,NH4Cl,and ZnS.Identify the precipitate formed after the addition of 6 mol L-1 HCl,followed by the addition of H2S and 0.2 mol L-1 HCl,and subsequently the addition of OH- to a pH of 8.

A 1.0 L buffer solution is 0.250 mol L-1 CH3COOH and 0.050 mol L-1 CH3COOLi.Which of the following actions will exceed the capacity of the buffer?

A 100.0 mL sample of 0.10 mol L-1 NH3 is titrated with 0.10 mol L-1 HNO3.Determine the pH of the solution after the addition of 100.0 mL of HNO3.The Kb of NH3 is 1.8 × 10-5.

A 100.0 mL sample of 0.10 mol L-1 NH3 is titrated with 0.10 mol L-1 HNO3.Determine the pH of the solution after the addition of 50.0 mL of HNO3.The Kb of NH3 is 1.8 × 10-5.

Which of the following is TRUE?

Determine the molar solubility of BaF2 in pure water.Ksp for BaF2 = 2.45 × 10-5.

Calculate the molar solubility of thallium chloride (TlCl)in 0.50 mol L-1 NaCl at 25 °C.Ksp for TlCl is 1.7×10−41.7 \times 10 ^{- 4}1.7×10−4

If the pKa of HCOOH is 3.74 and the pH of an HCOOH/HCOONa solution is 3.11,which of the following is TRUE?

When titrating a strong monoprotic acid with KOH at 25 °C,the

Explain the common ion effect with respect to molar solubility.

What is the pH of a solution made by mixing 10.00 mL of 0.10 mol L-1 acetic acid with 10.00 mL of 0.10 mol L-1 KOH? Assume that the volumes of the solutions are additive.Ka = 1.8×10−51.8 \times 10^{ - 5}1.8×10−5 for CH3COOH.

What is the pH of a solution prepared by mixing 50.00 mL of 0.10 mol L-1 methylamine,CH3NH2,with 20.00 mL of 0.10 mol L-1 methylammonium chloride,CH3NH3Cl? Assume that the volume of the solutions are additive and that Kb = 3.70 × 10-4 for methylamine.

Give the name of the compound that is in antifreeze and is toxic to pets.

A 25.0 mL sample of 0.150 mol L-1 butanoic acid is titrated with a 0.150 mol L-1 NaOH solution.What is the pH after 13.3 mL of base is added? The KaK _ { a }Ka​ of butanoic acid is 1.5 × 10-5.

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If the pK_aof HCOOH is 3.74 and the pH of an HCOOH/HCOONabuffer solution is 3.89,which of the following is TRUE?

Calculate the pH of a buffer that is 0.225 mol L^-¹ CH₃COOH and 0.162 mol L^-1 CH₃COOK.The K_a for CH₃COOH is 1.8 × 10^-5.

In which of the following solutions would solid PbBr₂ be expected to be the least soluble at 25 °C?

A sample contains Ba₃(PO₄)₂,CdS,AgCl,NH₄Cl,and ZnS.Identify the precipitate formed after the addition of 6 mol L^-1 HCl,followed by the addition of H₂S and 0.2 mol L^-1 HCl,and subsequently the addition of OH^- to a pH of 8.

A 1.0 L buffer solution is 0.250 mol L^-1 CH₃COOH and 0.050 mol L^-1 CH₃COOLi.Which of the following actions will exceed the capacity of the buffer?

A 100.0 mL sample of 0.10 mol L^-1 NH₃ is titrated with 0.10 mol L^-1 HNO₃.Determine the pH of the solution after the addition of 100.0 mL of HNO₃.The K_b of NH₃ is 1.8 × 10^-5.

A 100.0 mL sample of 0.10 mol L^-1 NH₃ is titrated with 0.10 mol L^-1 HNO₃.Determine the pH of the solution after the addition of 50.0 mL of HNO₃.The K_b of NH₃ is 1.8 × 10^-5.

Determine the molar solubility of BaF₂in pure water.K_sp for BaF₂ = 2.45 × 10^-5.

Calculate the molar solubility of thallium chloride (TlCl)in 0.50 mol L^-1 NaCl at 25 °C.K_sp for TlCl is $1.7 \times 10 ^{- 4}$

If the pKa of HCOOH is 3.74 and the pH of an HCOOH/HCOONasolution is 3.11,which of the following is TRUE?

What is the pH of a solution made by mixing 10.00 mL of 0.10 mol L^-1 acetic acid with 10.00 mL of 0.10 mol L^-1 KOH? Assume that the volumes of the solutions are additive.K_a = $1.8 \times 10^{ - 5}$ for CH₃COOH.

What is the pH of a solution prepared by mixing 50.00 mL of 0.10 mol L^-1 methylamine,CH₃NH₂,with 20.00 mL of 0.10 mol L^-1 methylammonium chloride,CH₃NH₃Cl? Assume that the volume of the solutions are additive and that K_b = 3.70 × 10^-4 for methylamine.

A 25.0 mL sample of 0.150 mol L^-1 butanoic acid is titrated with a 0.150 mol L^-1 NaOH solution.What is the pH after 13.3 mL of base is added? The $K _ { a }$ of butanoic acid is 1.5 × 10^-5.