Question 1

Osmotic pressure is a function of

Accepted Answer

A)  humidity.
B)  solute size.
C)  solute concentration.
D)  van der Waals forces.
E)  solute vapor pressure.F) A) and C)
G) C) and E)

Question 2

You prepare a solution by mixing 50 mL 0.10 M sodium acetate and 150 mL 1.0 M acetic acid (pKa 4.76).
a.Calculate the pH of this solution.
b.Can this solution be used effectively as a buffer (explain your answer)?

Accepted Answer

a.50 × 10⁻³ L × 0.10 mol/L acetate = 5.0 ×...

Question 3

Rank the following interactions in order of increasing strength (start with the weakest interaction) .

Accepted Answer

A)  ionic interactions,hydrogen bonds,London dispersion forces,covalent bonds
B)  London dispersion forces,hydrogen bonds,ionic interactions,covalent bonds
C)  London dispersion forces,ionic interactions,hydrogen bonds,covalent bonds
D)  covalent bonds,London dispersion forces,ionic interactions,hydrogen bonds
E)  hydrogen bonds,London dispersion forces,ionic interactions,covalent bondsF) A) and B)
G) None of the above B

Question 4

Which of the following statements about hydrophobic interactions is not true?

Accepted Answer

A)  They are caused by hydrophobic molecules interacting strongly with each other.
B)  They are the driving force for micelle formation.
C)  When nonpolar molecules come in contact with water,a highly-ordered shell of water molecules forms at the interface between the nonpolar molecules and water.A hydrophobic interaction is caused by the desire of water molecules to regain the entropy lost during this organization around the nonpolar substance by excluding the substance from interaction with water molecules.
D)  They are entropy driven.
E)  They are the main driving force for protein folding into three dimensional structures.F) B) and C)
G) A) and C)

Question 5

The pH of blood is affected by

Accepted Answer

A)  the reaction of CO2 with H2O to form carbonic acid.
B)  the ionization of aqueous carbonic acid to hydronium ions and the bicarbonate anions.
C)  the decrease of the blood pH due to the production of hydronium ions.
D)  the excretion of bicarbonate and ammonium ions from the kidneys.
E)  all of the aboveF) B) and D)
G) A) and B)

Question 6

A solution is made by mixing 1.0 mL of 1.0 M acetic acid (pK = 4.76,Ka = 1.74 x 10-5 ) with one 999 mL of pure water.Calculate the pH of the resulting solution (assume the total volume is 1.0 L) .

Accepted Answer

A)  10.1
B)  3) 0
C)  1) 0
D)  3) 9
E)  1) 32F) A) and E)
G) A) and D)

Question 7

Matching

-A solution containing a weak acid (pK = 7.5) and its conjugate base at pH of 8.5 has a good capacity to buffer the addition of ______.

Accepted Answer

A)   hydrogen bond
B)   rotational 
C)   H3PO4
D)   H2PO4–
E)   HPO4 2–F)  disordered G)  positive entropy H)  negative entropy  I)  higher electronegativity J)  insolubleK)  tetrahedral arrangement L)  acidM)  baseN)  only partially ionizedO) A) and I)
P) A) and J)

Question 8

Phosphoric acid is a polyprotic acid,with pK values of 2.14,6.86,and 12.38.Which ionic form predominates at pH 9.3?

Accepted Answer

A)  H3PO4
B)  H2PO41−
C)  HPO42−
D)  PO43−
E)  none of the aboveF) All of the above
G) None of the above

Question 9

Matching

-The polarity of the O-H bond is caused by the ______ of oxygen relative to that of hydrogen.

Accepted Answer

A)   hydrogen bond
B)   rotational 
C)   H3PO4
D)   H2PO4–
E)   HPO4 2–F)  disordered G)  positive entropy H)  negative entropy  I)  higher electronegativity J)  insolubleK)  tetrahedral arrangement L)  acidM)  baseN)  only partially ionizedO) I) and L)
P) E) and J)

Question 10

Biological processes can be best understood in the context of water.
a.What effect does water have on the noncovalent interactions between either charged or polar groups/molecules?
b.Why is this effect important with respect to biochemical processes?

Accepted Answer

a.Water reduces the strength of those in...

Question 11

The pH at the midpoint in the titration of an acid with a base is

Accepted Answer

A)  equal to the pK of the corresponding acid.
B)  equal to the pK of the corresponding base.
C)  equal to 14 minus the pK of the corresponding acid.
D)  equal to 14 plus the pK of the corresponding base.
E)  none of the aboveF) A) and B)
G) A) and C)

Question 12

Matching

-A strong acid is completely ionized in water,whereas a weak acid is ______.

Accepted Answer

A)   hydrogen bond
B)   rotational 
C)   H3PO4
D)   H2PO4–
E)   HPO4 2–F)  disordered G)  positive entropy H)  negative entropy  I)  higher electronegativity J)  insolubleK)  tetrahedral arrangement L)  acidM)  baseN)  only partially ionizedO) D) and H)
P) M) and N) N

Question 13

Matching

-A phosphate buffer solution at pH = pK1 = 2.15 would have equal amounts of phosphate in the ______ form and the H2PO4- form.

Accepted Answer

A)   hydrogen bond
B)   rotational 
C)   H3PO4
D)   H2PO4–
E)   HPO4 2–F)  disordered G)  positive entropy H)  negative entropy  I)  higher electronegativity J)  insolubleK)  tetrahedral arrangement L)  acidM)  baseN)  only partially ionizedO) None of the above
P) A) and D)

Question 14

Ice

Accepted Answer

A)  is a crystal of water molecules packed in an open structure stabilized by hydrogen bonds.
B)  is less dense than liquid water.
C)  contains 17% more hydrogen bonds then water.
D)  All of the statements above are true.
E)  None of the statements above are true.F) A) and D)
G) B) and E)

Question 15

Matching

-The insolubility of nonpolar molecules in water is due to the large ______,which is the result of water molecules forming an ordered network surrounding nonpolar molecules.

Accepted Answer

A)   hydrogen bond
B)   rotational 
C)   H3PO4
D)   H2PO4–
E)   HPO4 2–F)  disordered G)  positive entropy H)  negative entropy  I)  higher electronegativity J)  insolubleK)  tetrahedral arrangement L)  acidM)  baseN)  only partially ionizedO) A) and E)
P) C) and M) H

Question 16

Fatty acids such as palmitate and oleate are usually characterized as

Accepted Answer

A)  hydrophobic.
B)  hydrophilic.
C)  polar.
D)  water soluble.
E)  amphiphilic.F) A) and D)
G) All of the above

Question 17

Kw,the ionization constant of water,is _____ at _____.

Accepted Answer

A)  10-7;25°C
B)  107;25K
C)  1014;25°C
D)  10-14;25°C
E)  10-14;0°CF) C) and D)
G) D) and E)

Question 18

Urea is a water-soluble product of nitrogen metabolism.How many hydrogen bonds can one urea molecule donate to surrounding water molecules?

Accepted Answer

A)  2
B)  3
C)  4
D)  5
E)  6F) None of the above
G) B) and C)

Question 19

In the energetics of transferring hydrocarbons from water to nonpolar solvents,the factor T Δ\DeltaΔ S is commonly

Accepted Answer

A)  negative.
B)  positive.
C)  unmeasurable.
D)  unimportant.
E)  assumed to be zero. F) A) and E)
G) None of the above

Question 20

The pK1 of citric acid is 3.09.What is the citric acid : monosodium citrate ratio in a 1.0 M citric acid solution with a pH of 2.09?

Accepted Answer

A)  10:1
B)  1:1
C)  1:10
D)  10:11
E)  1:11F) None of the above
G) A) and C)

Exam 2: Water

Osmotic pressure is a function of

Correct AnswerverifiedShow Answer

You prepare a solution by mixing 50 mL 0.10 M sodium acetate and 150 mL 1.0 M acetic acid (pKa 4.76). a.Calculate the pH of this solution. b.Can this solution be used effectively as a buffer (explain your answer)?

Correct Answerverifieda.50 × 10−3 L × 0.10 mol/L acetate = 5.0 ×...View AnswerShow Answer

Rank the following interactions in order of increasing strength (start with the weakest interaction) .

Correct AnswerverifiedB

Which of the following statements about hydrophobic interactions is not true?

Correct AnswerverifiedShow Answer

The pH of blood is affected by

Correct AnswerverifiedShow Answer

A solution is made by mixing 1.0 mL of 1.0 M acetic acid (pK = 4.76,Ka = 1.74 x 10-5 ) with one 999 mL of pure water.Calculate the pH of the resulting solution (assume the total volume is 1.0 L) .

Correct AnswerverifiedShow Answer

Matching -A solution containing a weak acid (pK = 7.5) and its conjugate base at pH of 8.5 has a good capacity to buffer the addition of ______.

Correct AnswerverifiedShow Answer

Phosphoric acid is a polyprotic acid,with pK values of 2.14,6.86,and 12.38.Which ionic form predominates at pH 9.3?

Correct AnswerverifiedShow Answer

Matching -The polarity of the O-H bond is caused by the ______ of oxygen relative to that of hydrogen.

Correct AnswerverifiedShow Answer

Biological processes can be best understood in the context of water. a.What effect does water have on the noncovalent interactions between either charged or polar groups/molecules? b.Why is this effect important with respect to biochemical processes?

Correct Answerverifieda.Water reduces the strength of those in...View AnswerShow Answer

The pH at the midpoint in the titration of an acid with a base is

Correct AnswerverifiedShow Answer

Matching -A strong acid is completely ionized in water,whereas a weak acid is ______.

Correct AnswerverifiedN

Matching -A phosphate buffer solution at pH = pK1 = 2.15 would have equal amounts of phosphate in the ______ form and the H2PO4- form.

Correct AnswerverifiedShow Answer

Ice

Correct AnswerverifiedShow Answer

Matching -The insolubility of nonpolar molecules in water is due to the large ______,which is the result of water molecules forming an ordered network surrounding nonpolar molecules.

Correct AnswerverifiedH

Fatty acids such as palmitate and oleate are usually characterized as

Correct AnswerverifiedShow Answer

Kw,the ionization constant of water,is _____ at _____.

Correct AnswerverifiedShow Answer

Urea is a water-soluble product of nitrogen metabolism.How many hydrogen bonds can one urea molecule donate to surrounding water molecules?

Correct AnswerverifiedShow Answer

In the energetics of transferring hydrocarbons from water to nonpolar solvents,the factor T Δ\DeltaΔ S is commonly

Correct AnswerverifiedShow Answer

The pK1 of citric acid is 3.09.What is the citric acid : monosodium citrate ratio in a 1.0 M citric acid solution with a pH of 2.09?

Correct AnswerverifiedShow Answer

Correct Answer
verified

You prepare a solution by mixing 50 mL 0.10 M sodium acetate and 150 mL 1.0 M acetic acid (pK_a 4.76). a.Calculate the pH of this solution. b.Can this solution be used effectively as a buffer (explain your answer)?

Correct Answer
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a.50 × 10⁻³ L × 0.10 mol/L acetate = 5.0 ×...
View Answer

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B

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A solution is made by mixing 1.0 mL of 1.0 M acetic acid (pK = 4.76,K_a = 1.74 x 10^-5 ) with one 999 mL of pure water.Calculate the pH of the resulting solution (assume the total volume is 1.0 L) .

Correct Answer
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a.Water reduces the strength of those in...
View Answer

Correct Answer
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Correct Answer
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N

Matching -A phosphate buffer solution at pH = pK₁ = 2.15 would have equal amounts of phosphate in the ______ form and the H₂PO₄^- form.

Correct Answer
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H

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K_w,the ionization constant of water,is _ at _.

Correct Answer
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In the energetics of transferring hydrocarbons from water to nonpolar solvents,the factor T $\Delta$ S is commonly

Correct Answer
verified

The pK₁ of citric acid is 3.09.What is the citric acid : monosodium citrate ratio in a 1.0 M citric acid solution with a pH of 2.09?

Correct Answer
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