Chem 238 Lab Final Exam Questions with
100% Correct Answers
What are the derivatives of carboxylic acids?
esters, acid chlorides, amides
What is the first step in the Fischer esterification?
protonation of the carbonyl of the carboxylic acid
What kind of reaction does alkyl acid chloride show with water?
exothermic
What is the product of ammonolysis of benzoyl chloride?
benzamide
What does the structure of an azo dye require?
benzene rings and -N=N- (azo group)
The Grignard reagent, n-butylmagnesium bromide, may be classified as...
carbon nucleophile
The analogy between a chemical bond and a mechanical spring is very approximate
because electrons and atoms are governed by...
quantum mechanics
Why is UVC sunlight less dangerous than UVB?
UVC radiation is absorbed by ozone
In the nitration of methyl benzoate, which step is rate determining?
, addition of electrophile to benzene ring
What type of bond links amino acids together to make peptides?
amide bond
What structure does a positive Iodoform test indicate?
methyl carbonyls, methyl secondary alcohol
-ethanal is the only aldehyde
What does a negative iodoform test look like?
clear solution
What does a positive Tollen's test mean?
aldehyde
What does a negative Tollen's test mean?
ketone
What do you look at for picking a TLC solvent for multiple compounds?
the solvent that allows the compounds to reach the highest Rf values
When a molecule absorbs UV or visible light, what takes place?
electrons in lower molecule orbitals are excited into orbitals of higher energy
What combination of reagents forms a secondary alcohol?
Grignard reagent and an aldehyde
List some polyamide fabrics
wool, silk, nylon, aramid
100% Correct Answers
What are the derivatives of carboxylic acids?
esters, acid chlorides, amides
What is the first step in the Fischer esterification?
protonation of the carbonyl of the carboxylic acid
What kind of reaction does alkyl acid chloride show with water?
exothermic
What is the product of ammonolysis of benzoyl chloride?
benzamide
What does the structure of an azo dye require?
benzene rings and -N=N- (azo group)
The Grignard reagent, n-butylmagnesium bromide, may be classified as...
carbon nucleophile
The analogy between a chemical bond and a mechanical spring is very approximate
because electrons and atoms are governed by...
quantum mechanics
Why is UVC sunlight less dangerous than UVB?
UVC radiation is absorbed by ozone
In the nitration of methyl benzoate, which step is rate determining?
, addition of electrophile to benzene ring
What type of bond links amino acids together to make peptides?
amide bond
What structure does a positive Iodoform test indicate?
methyl carbonyls, methyl secondary alcohol
-ethanal is the only aldehyde
What does a negative iodoform test look like?
clear solution
What does a positive Tollen's test mean?
aldehyde
What does a negative Tollen's test mean?
ketone
What do you look at for picking a TLC solvent for multiple compounds?
the solvent that allows the compounds to reach the highest Rf values
When a molecule absorbs UV or visible light, what takes place?
electrons in lower molecule orbitals are excited into orbitals of higher energy
What combination of reagents forms a secondary alcohol?
Grignard reagent and an aldehyde
List some polyamide fabrics
wool, silk, nylon, aramid
