Question 1

Intracellular fluids and the fluids surrounding cells in multicellular organisms are full of dissolved substances,including nucleotides,amino acids,proteins and ions.The total concentration of substances determines the colligative properties of a fluid.Osmosis is one of several such colligative properties.
a.Give the definition of osmosis.
b.Eukaryotic cells are aqueous solutions surrounded by semipermeable membranes.Consequently,incubation of a cell in a solution of lower osmotic pressure would cause the cell to swell up and burst.Discuss two solutions that have developed during evolution to solve this problem.

Accepted Answer

a.Osmosis is the movement of solvent (wa...

Question 2

Matching

-Translational and ______ thermal motion causes liquid water molecules to reorient approximately every 10-12 seconds.

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 ionized

Question 3

Sheets composed of two layers of amphipathic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center that form in water are called

Accepted Answer

A)  micelles.
B)  liposomes.
C)  vacuoles.
D)  bilayer membranes.
E)  none of the above

Question 4

Matching

-Octane molecules dispersed in water tend to aggregate because that allows water molecules to be more ______.

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 ionized

Question 5

_____ is exceptionally soluble in water due to the formation of hydrogen bonds.

Accepted Answer

A)  NaCl
B)  Benzene
C)  Sodium palmitate
D)  Ethanol
E)  Oxygen

Question 6

The pH of a 0.1 M solution of sodium acetate would be

Accepted Answer

A)  basic,because of the acetate ion reacts with water to form acetic acid and OH-.
B)  acidic,because the acetate ion is acidic.
C)  acidic,because the acetate ion forms acetic acid.
D)  neutral,because salts are neither acidic nor basic.
E)  basic,because the Na+ ionizes and combines with OH-.

Question 7

You mix 999 mL pure water and 1 mL of 2.0 M NaOH.Calculate the pH of the resulting solution.(assume the total volume is 1.0 L) .

Accepted Answer

A)  0) 3
B)  0) 7
C)  2) 7
D)  11.3
E)  13.7

Question 8

Which of the following statements about water is not true?

Accepted Answer

A)  It has a high dielectric constant.
B)  It dissolves salts and polar substances.
C)  It can form two hydrogen bonds per water molecule.
D)  It packs in a hexagonal (honeycomb) shaped lattice when the temperature falls below 0°C.
E)  In the liquid state it is only 15% less hydrogen bonded than in the solid state at 0°C.

Question 9

The boiling point of water is 264°C higher than the boiling point of methane because

Accepted Answer

A)  the molecular mass of methane is much lower than that of water.
B)  methane molecules tend to avoid contact with each other.
C)  water molecules are connected to each other by H-bonds.
D)  methane molecules do not undergo London dispersion forces.
E)  all of the above

Question 10

To make an acetate buffer at pH 4.76 starting with 500 mL of 0.1 M sodium acetate (pK acetic acid = 4.76) ,you could add

Accepted Answer

A)  0) 1 mol of NaOH.
B)  0) 2 mol of HCl.
C)  0) 025 mol of HCl.
D)  0) 1 mol of HCl.
E)  You can't make a buffer by adding HCl or NaOH.

Question 11

The pKa of carbonic acid is 6.35.A solution is made by combining 50 mL 1.0 M carbonic acid,2.0 mL 5.0 M KOH and 448 mL pure water (assume the total volume is 500 mL).Calculate the pH of the resulting solution.

Accepted Answer

50 × 10⁻³ L × 1.0 mol/L carbonic acid = 50...

Question 12

Physical properties that depend on the amounts of various species,rather than the identities of those species,are called

Accepted Answer

A)  osmotic properties.
B)  hydrophobic properties.
C)  London dispersion forces.
D)  aggregate properties.
E)  colligative properties.

Question 13

Matching

-Phosphate (pK1 = 2.15,pK2 = 6.82,and pK3 = 12.38) will be mostly in the HPO42- form at pH 7.2.At pH 5.82 it is mostly in the ______ 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 ionized

Question 14

A solution is made by mixing 0.05 mL of 1.0 M HCl with 999.95 mL of pure water.Calculate the pH of the resulting solution (assume the total volume is 1.0 L) .

Accepted Answer

A)  2) 7
B)  4) 3
C)  9) 7
D)  7) 0
E)  5) 0

Question 15

You mix equal volumes of 0.05 M NaH2PO4 and 0.05 M Na2HPO4 (pK's for phosphoric acid are 2.15,6.82 and 12.38) .Which of the following best describes the resulting solution?

Accepted Answer

A)  pH 2.15 and poorly buffered
B)  pH 2.15 and well buffered
C)  pH 6.82 and well buffered
D)  pH 12.38 and well buffered
E)  pH 6.82 and poorly buffered

Question 16

The hydrophobic effect is an important driving force for protein folding and for the assembly of molecules into cellular structures.
a.Give the definition of the hydrophobic effect
b.What are amphiphilic (amphipathic)molecules?
c.Which cellular structures are composed of many amphipathic molecules that are driven together under the influence of the hydrophobic effect?

Accepted Answer

a.It is defined as the tendenc...

Question 17

Hydrophobic interactions between nonpolar molecules

Accepted Answer

A)  result from the tendency of water to maximize contact with nonpolar molecules.
B)  are the result of strong attractions between nonpolar molecules.
C)  are the result of strong repulsion between water and nonpolar molecules.
D)  depend on strong permanent dipoles in the nonpolar molecules.
E)  require the presence of surrounding water molecules.

Question 18

Globules of up to several thousand amphiphilic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center that form in water are called

Accepted Answer

A)  micelles.
B)  liposomes.
C)  vacuoles.
D)  bilayer membranes.
E)  none of the above

Question 19

What is the approximate pKa of a weak acid HA if a solution 0.1 M HA and 0.3 M A- has a pH of 6.5?

Accepted Answer

A)  5) 8
B)  6) 0
C)  6) 2
D)  6) 4
E)  6) 6

Exam 2: Water

Matching -Octane molecules dispersed in water tend to aggregate because that allows water molecules to be more ______.

Correct Answer
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Hydrophobic interactions between nonpolar molecules

Correct Answer
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_____ is exceptionally soluble in water due to the formation of hydrogen bonds.

Correct Answer
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The pK_a of carbonic acid is 6.35.A solution is made by combining 50 mL 1.0 M carbonic acid,2.0 mL 5.0 M KOH and 448 mL pure water (assume the total volume is 500 mL).Calculate the pH of the resulting solution.

Correct Answer
verified
50 × 10⁻³ L × 1.0 mol/L carbonic acid = 50...
View Answer

Globules of up to several thousand amphiphilic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center that form in water are called

Correct Answer
verified

What is the approximate pK_a of a weak acid HA if a solution 0.1 M HA and 0.3 M A^- has a pH of 6.5?

Correct Answer
verified

You mix equal volumes of 0.05 M NaH₂PO₄ and 0.05 M Na₂HPO₄ (pK's for phosphoric acid are 2.15,6.82 and 12.38) .Which of the following best describes the resulting solution?

Correct Answer
verified

To make an acetate buffer at pH 4.76 starting with 500 mL of 0.1 M sodium acetate (pK acetic acid = 4.76) ,you could add

Correct Answer
verified

A solution is made by mixing 0.05 mL of 1.0 M HCl with 999.95 mL of pure water.Calculate the pH of the resulting solution (assume the total volume is 1.0 L) .

Correct Answer
verified

Sheets composed of two layers of amphipathic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center that form in water are called

Correct Answer
verified

You mix 999 mL pure water and 1 mL of 2.0 M NaOH.Calculate the pH of the resulting solution.(assume the total volume is 1.0 L) .

Correct Answer
verified

Matching -Phosphate (pK₁ = 2.15,pK₂ = 6.82,and pK₃ = 12.38) will be mostly in the HPO₄^2- form at pH 7.2.At pH 5.82 it is mostly in the ______ form.

Correct Answer
verified

The pH of a 0.1 M solution of sodium acetate would be

Correct Answer
verified

Correct Answer
verified
a.Osmosis is the movement of solvent (wa...
View Answer

Correct Answer
verified
a.It is defined as the tendenc...
View Answer

Physical properties that depend on the amounts of various species,rather than the identities of those species,are called

Correct Answer
verified

Which of the following statements about water is not true?

Correct Answer
verified

The boiling point of water is 264°C higher than the boiling point of methane because

Correct Answer
verified

Matching -Translational and ______ thermal motion causes liquid water molecules to reorient approximately every 10^-12 seconds.

Correct Answer
verified

Exam 2: Water

Matching -Octane molecules dispersed in water tend to aggregate because that allows water molecules to be more ______.

Correct AnswerverifiedShow Answer

Hydrophobic interactions between nonpolar molecules

Correct AnswerverifiedShow Answer

_____ is exceptionally soluble in water due to the formation of hydrogen bonds.

Correct AnswerverifiedShow Answer

The pKa of carbonic acid is 6.35.A solution is made by combining 50 mL 1.0 M carbonic acid,2.0 mL 5.0 M KOH and 448 mL pure water (assume the total volume is 500 mL).Calculate the pH of the resulting solution.

Correct Answerverified50 × 10−3 L × 1.0 mol/L carbonic acid = 50...View AnswerShow Answer

Globules of up to several thousand amphiphilic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center that form in water are called

Correct AnswerverifiedShow Answer

What is the approximate pKa of a weak acid HA if a solution 0.1 M HA and 0.3 M A- has a pH of 6.5?

Correct AnswerverifiedShow Answer

You mix equal volumes of 0.05 M NaH2PO4 and 0.05 M Na2HPO4 (pK's for phosphoric acid are 2.15,6.82 and 12.38) .Which of the following best describes the resulting solution?

Correct AnswerverifiedShow Answer

To make an acetate buffer at pH 4.76 starting with 500 mL of 0.1 M sodium acetate (pK acetic acid = 4.76) ,you could add

Correct AnswerverifiedShow Answer

A solution is made by mixing 0.05 mL of 1.0 M HCl with 999.95 mL of pure water.Calculate the pH of the resulting solution (assume the total volume is 1.0 L) .

Correct AnswerverifiedShow Answer

Sheets composed of two layers of amphipathic molecules arranged with the hydrophilic groups on the surface and the hydrophobic groups buried in the center that form in water are called

Correct AnswerverifiedShow Answer

You mix 999 mL pure water and 1 mL of 2.0 M NaOH.Calculate the pH of the resulting solution.(assume the total volume is 1.0 L) .

Correct AnswerverifiedShow Answer

Matching -Phosphate (pK1 = 2.15,pK2 = 6.82,and pK3 = 12.38) will be mostly in the HPO42- form at pH 7.2.At pH 5.82 it is mostly in the ______ form.

Correct AnswerverifiedShow Answer

The pH of a 0.1 M solution of sodium acetate would be

Correct AnswerverifiedShow Answer

Correct Answerverifieda.Osmosis is the movement of solvent (wa...View AnswerShow Answer

Correct Answerverifieda.It is defined as the tendenc...View AnswerShow Answer

Physical properties that depend on the amounts of various species,rather than the identities of those species,are called

Correct AnswerverifiedShow Answer

Which of the following statements about water is not true?

Correct AnswerverifiedShow Answer

The boiling point of water is 264°C higher than the boiling point of methane because

Correct AnswerverifiedShow Answer

Matching -Translational and ______ thermal motion causes liquid water molecules to reorient approximately every 10-12 seconds.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The pK_a of carbonic acid is 6.35.A solution is made by combining 50 mL 1.0 M carbonic acid,2.0 mL 5.0 M KOH and 448 mL pure water (assume the total volume is 500 mL).Calculate the pH of the resulting solution.

Correct Answer
verified
50 × 10⁻³ L × 1.0 mol/L carbonic acid = 50...
View Answer

Correct Answer
verified

What is the approximate pK_a of a weak acid HA if a solution 0.1 M HA and 0.3 M A^- has a pH of 6.5?

Correct Answer
verified

You mix equal volumes of 0.05 M NaH₂PO₄ and 0.05 M Na₂HPO₄ (pK's for phosphoric acid are 2.15,6.82 and 12.38) .Which of the following best describes the resulting solution?

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Matching -Phosphate (pK₁ = 2.15,pK₂ = 6.82,and pK₃ = 12.38) will be mostly in the HPO₄^2- form at pH 7.2.At pH 5.82 it is mostly in the ______ form.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
a.Osmosis is the movement of solvent (wa...
View Answer

Correct Answer
verified
a.It is defined as the tendenc...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Matching -Translational and ______ thermal motion causes liquid water molecules to reorient approximately every 10^-12 seconds.

Correct Answer
verified