click below
click below
Normal Size Small Size show me how
Chem 1052
exam4
Question | Answer |
---|---|
Combustion | the reaction of an alcohol with oxygen to produce CO2, H2O, and energy |
what happens when an organic comp is oxidized? | -There's an increase in number of C-O bonds ...... -There's a loss of H |
what happens when an organic comp is reduced? | -there's a decrease in number of C-O bonds ........ -there's a gain of H |
bond formed btwn alcohol molecs? | H bonds |
why are phenols weak acids | they have an -OH group that slightly ionizes |
what is the carbonyl group in an aldehyde | it has a carbonyl C bonded to one H atom |
what is the carbonyl group in a ketone | it has the carbonyl C bonded to 2 C atoms |
hemiacetals | C atoms that contain -OH group and an alkoxy group (-OR) |
when are hemiacetals formed | they are formed when an alcohol adds to an aldehyde or ketone in the presence of an acid catalyst |
what do hemiacetals react with | they react with a 2nd alcohol molec to produce an acetal |
acetal | -a C with 2 alkoxy groups (-OR) -are produced when a hemiacetal reacts with another alcohol molec |
cyclic acetals | -they form when an alcohol adds to a cyclic hemiacetal ********************** -the type of linkage that bonds glucose molecs to each other in formation of disaccharides and polysaccharides |
maltose | -a disaccharide consisting of 2 glucose molecs linked by an acetal bond ************* -has one glucose that retains the cyclic hemiacetal bond |
structural isomers | molecules that have the same formula but diff bonding arrangements |
stereoisomers | -have atoms that are bonded in the same sequence, but differ in the way they're arranged in space -molecs that are nonsuperimposable mirror images |
molecs are chiral when they are ______. | nonnsuperimposable |
nonsuperimposable | when something's mirror image can't be completely matched |
when are molecs achiral | when the mirror image of the molec is identical and can be superimposed on the original |
when are C atoms chiral | -when they have 4 diff atoms or groups *********** -when they are nonsuperimposable |
enantiomers | stereoisomers that cannot be superimposed |
what are the enantiomers of a chiral molec | -mirror images that cannot be superimposed on each other |
are achiral structures nonsuperimposable or superimposable? | superimposable |
what happens when the mirror image of an achiral structure is rotated? | -the structure is aligned with its initial structure ******** -its mirror image is superimposable |
what are the 3 types of carbs | monosaccharides disaccharides polysaccharides |
what do monosaccharides consist of | -3-6 C atoms ************* -a carbonyl group (aldehyde or ketone) ************* -several (-OH) groups |
what are the two types of structures of monosaccharides | aldoses ***** ketoses |
aldoses | -monosaccharide structure ********** -the carbonyl group on the first C is an aldehyde *********** -also has many (-OH) groups |
ketoses | -monosaccharide structure ************** -there's a ketone carbonyl group on the 2nd C ****************** -also has many (-OH) groups |
naming monosaccharides | -the names end in (-ose) ************ -may be named according to the # of C atoms (triose = 3 C atoms) |
naming aldoses | put aldo- in front of the monosaccharide name |
naming ketoses | put keto- in front of the monosaccharide name |
what are the most important monosaccharides | the hexoses of: -glucose -galactose -fructose |
when two monosaccharides combine in a dehydration rxn, what are the products? | water and acetal |
what happens hen monosaccharides are reduced | -the carbonyl group is turned into an alcohol group *********** -produces sugar alcohols called alditols (named by replacing -ose with -itol) |
what are the three most common disaccharides | maltose ***** lactose ****** sucrose |
maltose | -a disaccharide composed of two D-glucose molecs ****** -linked by a-1,4-glycosidic bond btwn a-OH on C1 of 1st glucose and -OH on C4 of 2nd glucose ******* -found in both a- and B- forms |
lactose | -a disaccharide of B-D-galactose and a- or B-D-glucose *********** -contains a B1,4-glycosidic bond ******************* -found in both a- and B- forms |
sucrose | -aka table sugar **************** -disaccharide of a-D-glucose and B-D-fructose *********** -has an a,B-1,2-glycosidic bond |
how do polysaccharides differ from one another | -differ in types of links btwn monosaccharides and the monosaccharides in the polymer -differ by amt of branching in the polymer |
what is the IUPAC name for Benzene | benzoic acid |
naming carboxylic acids (IUPAC) | 1.) identify longest C chain and replace (-e) in alkane name with (-oic acid) ************ 2.) give location and name of each sub by counting the carboxyl C as 1 |
how are carboxylic acids prepared | -by oxidizing primary alcohols or aldehydes **** -from oxidation of ethanol |
solubility of carboxylic acids with 1-5 C in water | very soluble in water |
polarity of carboxylic acids | -strongly polar ************* -have 2 polar groups: hydroxyl (-OH) and carbonyl (C=O) |
how do esters differ from carboxylic acids | they differ from carboxylic acids by replacement of (-OH) group with alkoxy group (-OR) |
esterification | -rxn of a carboxylic acid and alcohol in presence of an acid catalyst to produce an ester ******* -is a condensation rxn b/c it produces water |
naming esters (IUPAC) | 1.) write the name of the C chain from the alcohol as an alkyl group ******************* 2.) change the -ic acid of the acid name to -ate |
esters have higher BP's than _____ | have higher BP than for alkanes of similar mass |
esters have lower BP's than _____ | have lower BP than alcohols and carboxylic acids of similar mass b/c esters can't form H bonds with each other |
acid hydrolysis of esters | -an ester reacts with water to produce a carboxylic acid and an alcohol ******************* -a strong acid catalyst or an enzyme is required |
base hydrolysis | -aka saponification******* -rxn of an ester w/ a strong base************** -produces the salt of the carboxylic acid and an alcohol |
what does saponification of long-chain fatty acids produce? | it produces acid salts called "soaps" |