Question 1

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) insoluble
K) tetrahedral arrangement 
L) acid
M) base
N) only partially ionized 
A)  hydrogen bond 
B)  rotational 
C)  H3PO4 
D)  H2PO4– 
E)  HPO4 2–
F) disordered 
G) positive entropy 
H) negative entropy  
I) higher electronegativity 
J) insoluble
K) tetrahedral arrangement 
L) acid
M) base
N) only partially ionized

Question 2

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

Question 3

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

Question 4

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

Question 5

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 
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 6

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 7

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 8

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-. 
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 9

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. 
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 10

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

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

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. 
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 13

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 
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 14

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) insoluble
K) tetrahedral arrangement 
L) acid
M) base
N) only partially ionized 
A)  hydrogen bond 
B)  rotational 
C)  H3PO4 
D)  H2PO4– 
E)  HPO4 2–
F) disordered 
G) positive entropy 
H) negative entropy  
I) higher electronegativity 
J) insoluble
K) tetrahedral arrangement 
L) acid
M) base
N) only partially ionized

Question 15

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

Question 16

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

Question 17

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) insoluble
K) tetrahedral arrangement 
L) acid
M) base
N) only partially ionized 
A)  hydrogen bond 
B)  rotational 
C)  H3PO4 
D)  H2PO4– 
E)  HPO4 2–
F) disordered 
G) positive entropy 
H) negative entropy  
I) higher electronegativity 
J) insoluble
K) tetrahedral arrangement 
L) acid
M) base
N) only partially ionized

Question 18

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. 
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 19

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

Exam 2: Water

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.

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

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

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).

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?

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

Which of the following statements about water is not true?

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

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.

Hydrophobic interactions between nonpolar molecules

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

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

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).

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?

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

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

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

Introduction to the Chemistry of Life

Nucleotides, nucleic Acids, and Genetic Information

Amino Acids

Proteins: Primary Structure

Proteins: Three-Dimensional Structure

Protein Function Part I: Myoglobin and Hemoglobin

Carbohydrates

Lipids and Biological Membranes

Membrane Transport

Enzyme Catalysis

Enzyme Kinetics, inhibition and Control

Biochemical Signaling

Introduction to Metabolism

Glucose Catabolism

Glycogen Metabolism and Gluconeogenesis

Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Mammalian Fuel Metabolism: Integration and Regulation

Nucleotide Metabolism

Nucleic Acid Structure

DNA Replication, repair and Recombination

Transcription and Rna Processing

Protein Synthesis

Regulation of Gene Expression

Filters

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.

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?

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.

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

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?