Question 1

Provide two ways in which acid catalyzes ester hydrolysis.

Accepted Answer

In the first step,protonating the carbon

Question 2

How do enzymes differ from nonbiological catalysts?

Accepted Answer

A) They have specificity for the substrate. 
B) They have lower molecular weights than nonbiological catalysts. 
C) They require higher pressure to be functional. 
D) They require lower pH to be functional. 
E) They are more polar than nonbiological catalysts. 
A) They have specificity for the substrate. 
B) They have lower molecular weights than nonbiological catalysts. 
C) They require higher pressure to be functional. 
D) They require lower pH to be functional. 
E) They are more polar than nonbiological catalysts.

Question 3

Which of the following statements is not true about catalysts?

Accepted Answer

A) They can increase the rate of a chemical reaction. 
B) They can change the mechanism of a chemical reaction. 
C) They are changed in a chemical reaction. 
D) They participate in a chemical reaction. 
E) They can decrease the activation energy of a chemical reaction. 
A) They can increase the rate of a chemical reaction. 
B) They can change the mechanism of a chemical reaction. 
C) They are changed in a chemical reaction. 
D) They participate in a chemical reaction. 
E) They can decrease the activation energy of a chemical reaction.

Question 4

Which of the following sets of parameters are all altered when a reaction is carried out in the presence of a catalyst?

Accepted Answer

A) ΔG°,ΔH°,Keq 
B) Ea,free energy of activation,krate 
C) ΔG°,krate,Keq 
D) ΔH°,DS°,Ea 
E) ΔH°,ΔS°,krate 
A) ΔG°,ΔH°,Keq 
B) Ea,free energy of activation,krate 
C) ΔG°,krate,Keq 
D) ΔH°,DS°,Ea 
E) ΔH°,ΔS°,krate

Question 5

Which of the following is an intermediate in the metal-ion catalyzed reaction shown below?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V

Question 6

Describe the reaction coordinate diagram for a general-acid-catalyzed reaction.

Accepted Answer

A) one peak 
B) two peaks,second peak is larger 
C) two peaks,second peak is smaller 
D) two peaks,equal size 
E) three peaks,middle peak is larger 
A) one peak 
B) two peaks,second peak is larger 
C) two peaks,second peak is smaller 
D) two peaks,equal size 
E) three peaks,middle peak is larger

Question 7

Provide the two general ways that metal ions catalyze organic reactions.

Accepted Answer

They can increase electrophili

Question 8

Give the starting materials for the following products.

Accepted Answer

The answer of Give the starting materials for the following...

Question 9

Which of the following is the main difference among the active sites of all serine proteases?

Accepted Answer

A) the presence of serine residue at the active site 
B) the size and charge of the pocket at the active site 
C) the presence of histidine residue at the active site 
D) the presence of aspartate at the active site 
E) the hydrolysis of the peptide bond 
A) the presence of serine residue at the active site 
B) the size and charge of the pocket at the active site 
C) the presence of histidine residue at the active site 
D) the presence of aspartate at the active site 
E) the hydrolysis of the peptide bond

Question 10

Explain the large difference in the relative rates of the following hydrolysis reactions:

Accepted Answer

This large difference in the relative ra

Question 11

Which of the following residues are found at the active site of lysozyme?

Accepted Answer

A) His 57,Asp 102 
B) His 57,Asp 52 
C) Glu 35,His 57 
D) Asp 102,Glu 35 
E) Glu 35,Asp 52 
A) His 57,Asp 102 
B) His 57,Asp 52 
C) Glu 35,His 57 
D) Asp 102,Glu 35 
E) Glu 35,Asp 52

Question 12

An acid catalyst functions by donating ________ to a substrate.

Accepted Answer

A) a proton 
B) an electron 
C) an electron pair 
D) a nucleophile 
E) a molecule of water 
A) a proton 
B) an electron 
C) an electron pair 
D) a nucleophile 
E) a molecule of water

Question 13

Identify the factors that contribute to the catalytic ability of enzymes.

Accepted Answer

A) proper orientation of the reacting groups 
B) some amino acid side chain groups of the enzyme serve as catalysts 
C) some amino acid side chains stabilize transition states and intermediates 
D) metal ions in enzymes serve as catalysts 
E) all of the above 
A) proper orientation of the reacting groups 
B) some amino acid side chain groups of the enzyme serve as catalysts 
C) some amino acid side chains stabilize transition states and intermediates 
D) metal ions in enzymes serve as catalysts 
E) all of the above

Question 14

Which of the following represents the first step(s)in the mechanism involving general-base catalysis for the reaction shown below?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V

Question 15

Offer an explanation of how iodide catalyzes the hydrolysis of 1-chloropropane in aqueous base.

Accepted Answer

The iodide acts as a nucloephile and dis

Question 16

Explain the phenomenon known as molecular recognition.Give an example.

Accepted Answer

Molecular recognition is the recognition

Question 17

How does Zn2+ catalyze the hydrolysis of trifluoroacetate esters?

Accepted Answer

The interaction of Zn²⁺ with water yields

Question 18

Rank the following compounds in increasing order of reactivity in the intramolecular displacement of p-bromophenolate to form a cyclic anhydride.Explain your ranking.

Accepted Answer

B < C < A.B is slower than C since it ha

Question 19

The compound CH3OCH2CH2CH2CH2Br undergoes a solvolysis reaction in aqueous ethanol solution.Which of the following is evidence that a neighboring group effect is occurring?

Accepted Answer

A) CH3CH2CH2CH2Br reacts more slowly than CH3OCH2CH2CH2CH2Br does. 
B) The reaction is faster when the concentration of water is higher. 
C) The reaction is first order. 
D) HBr is a product of the reaction. 
A) CH3CH2CH2CH2Br reacts more slowly than CH3OCH2CH2CH2CH2Br does. 
B) The reaction is faster when the concentration of water is higher. 
C) The reaction is first order. 
D) HBr is a product of the reaction.

Question 20

Describe the first step of a specific-base-catalyzed dehydration of a hydrate.

Accepted Answer

A) Base abstracts a proton,electron pair from O-H bond goes to oxygen. 
B) Negative charge from oxygen forms double bond,hydroxide departs as leaving group. 
C) Base abstracts a proton,electron pair from O-H bond forms a double bond,hydroxide departs as leaving group. 
D) Hydroxide departs as leaving group,then negative charge from oxygen forms a double bond. 
E) Electron pair from O-H bond forms a double bond,base abstracts a proton. 
A) Base abstracts a proton,electron pair from O-H bond goes to oxygen. 
B) Negative charge from oxygen forms double bond,hydroxide departs as leaving group. 
C) Base abstracts a proton,electron pair from O-H bond forms a double bond,hydroxide departs as leaving group. 
D) Hydroxide departs as leaving group,then negative charge from oxygen forms a double bond. 
E) Electron pair from O-H bond forms a double bond,base abstracts a proton.

Exam 22: Catalysis in Organic Reactions and in Enzymatic Reactions

Provide two ways in which acid catalyzes ester hydrolysis.

How do enzymes differ from nonbiological catalysts?

Which of the following statements is not true about catalysts?

Which of the following sets of parameters are all altered when a reaction is carried out in the presence of a catalyst?

Which of the following is an intermediate in the metal-ion catalyzed reaction shown below?

Describe the reaction coordinate diagram for a general-acid-catalyzed reaction.

Provide the two general ways that metal ions catalyze organic reactions.

Give the starting materials for the following products.

Which of the following is the main difference among the active sites of all serine proteases?

Explain the large difference in the relative rates of the following hydrolysis reactions:

Which of the following residues are found at the active site of lysozyme?

An acid catalyst functions by donating ________ to a substrate.

Identify the factors that contribute to the catalytic ability of enzymes.

Which of the following represents the first step(s)in the mechanism involving general-base catalysis for the reaction shown below?

Offer an explanation of how iodide catalyzes the hydrolysis of 1-chloropropane in aqueous base.

Explain the phenomenon known as molecular recognition.Give an example.

How does Zn2+ catalyze the hydrolysis of trifluoroacetate esters?

Rank the following compounds in increasing order of reactivity in the intramolecular displacement of p-bromophenolate to form a cyclic anhydride.Explain your ranking.

The compound CH3OCH2CH2CH2CH2Br undergoes a solvolysis reaction in aqueous ethanol solution.Which of the following is evidence that a neighboring group effect is occurring?

Describe the first step of a specific-base-catalyzed dehydration of a hydrate.

Remembering General Chemistry: Electronic Structure and Bonding

Acids and Bases: Central to Understanding Organic Chemistry

An Introduction to Organic Compounds: Nomenclature, physical Properties, and Structure

Isomers: the Arrangement of Atoms in Space

Alkenes: Structure,nomenclature,and an Introduction to Reactivity - Thermodynamics and Kinetics

The Reactions of Alkenes - the Stereochemistry of Addition Reactions

The Reactions of Alkynes - Introduction to Multistep Synthesis

Delocalized Electrons: Their Effect on Stability, pka, and the Products of a Reaction - Aromaticity and Electronic Effects: an Introduction to the Reactions of Benzene

Substitution and Elimination Reactions of Alkyl Halides

Reactions of Alcohols, ethers, epoxides, amines and Sulfur-Containing Compounds

Organometallic Compounds

Radicals

Mass Spectrometry,infrared Spectroscopy,and Uvvis Spectroscopy

Nmr Spectroscopy

Reactions of Carboxylic Acids and Carboxylic Acid Derivatives

Reactions of Aldehydes and Ketones

Reactions at the Α-Carbon

Reactions of Benzene and Substituted Benzenes

More About Amines - Reactions of Heterocylic Compounds

The Organic Chemistry of Carbohydrates

Amino Acids,peptides,and Proteins

The Organic Chemistry of the Coenzymes, compounds Derived From Vitamins

The Organic Chemistry of the Metabolic Pathways

The Organic Chemistry of Lipids

The Chemistry of the Nucleic Acids

Synthetic Polymers

Pericyclic Reactions

Filters

How does Zn²⁺ catalyze the hydrolysis of trifluoroacetate esters?

The compound CH₃OCH₂CH₂CH₂CH₂Br undergoes a solvolysis reaction in aqueous ethanol solution.Which of the following is evidence that a neighboring group effect is occurring?