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57 Cards in this Set
- Front
- Back
Lucas test
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Used to distinguish between a primary, secondary and tertiary alcohols.
-- primary alcohol and phenols will have no reaction. -- secondary alcohols will form a white layer after 10 minutes of heat. -- tertiary alcohols will form an immediate white layer. -- ketones and aldehydes have no reaction. |
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What are some differences between alcohols and phenol?
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- Phenol is an OH group on an aromatic ring.
- Phenols are acidic while alcohols are not. - Phenols are much more toxic. - Phenols yield a purple color change in the Iron (III) Cl test while alcohols have no change. |
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Chromic acid test
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Used to distinguish between primary, secondary and tertiary alcohols.
-- primary alcohols turn blue-green -- secondary alcohols turn blue-green -- tertiary alcohols have no reaction -- phenols yield a brown, tarry mass -- aldehydes turn blue-green -- ketones have no reaction |
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Iodoform test
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Used to distinguish phenols and ethyl alcohols or methyl ketones.
-- only secondary/ethyl alcohols will produce a yellow ppt -- primary alcohols, tertiary alcohols and aldehydes will not react -- phenols will produce a yellow ppt -- methyl ketones will produce a yellow ppt |
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Which will dissolve in a basic solution? Alcohols, phenols, both? Why?
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Phenols are acidic and will dissolve in a basic solution. Alcohols are not acidic and will not dissolve in a basic solution.
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Iron (III) Cl test
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Used to distinguish between alcohols and phenols.
-- Phenols turn a green - purple color -- Alcohols, aldehydes and ketones do not react. |
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What is a functional group?
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An atom or group of atoms within a molecule that shows a characteristic set of chemical and physical properties.
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What makes many alcohols water soluble?
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The presence of the polar hydroxyl group which is able to form hydrogen bonds.
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Which would react with a base and why? primary alcohol, secondary alcohol, tertiary alcohol or a phenol
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The phenol because it is acidic.
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Name the color test that is specific for phenol and what is the reaction?
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Iron (III) Cl test, phenols turn a green-purple color.
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When would formation of a derivative be a necessary step?
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Specific aldehydes and ketones cannot be determined using the 2,4 DNP test, just their presence. Derivatives are formed when you want to identify a specific aldehyde or ketone.
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2,4 DNP test
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Used to distinguish aldehydes and ketones from alcohols.
-- Aldehydes and ketones give a yellow - red ppt -- Alcohols and phenols have no reaction |
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Tollen's test
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Used to distinguish aldehydes from other compounds.
-- Aldehydes will yield a 'silver mirror' -- All other compounds will have no reaction |
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What is the active agent in aspirin?
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salicylic acid
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Why can't salicylic acid be taken without being made into an ester?
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salicylic acid is too harsh for the mouth, esophagus and stomach due to the phenol group and carboxyl group.
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What two compounds form aspirin?
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salicylic acid and acetic anhydride
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What is acetylsalicyclic acid?
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Aspirin
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How do buffering agents mitigate the harmful effects of aspirin?
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They neutralize the acid.
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In the aspirin lab, why is cold water added to the solution and the flask placed in a cold water bath prior to filtering it?
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The water added to the solution destroys the remaining unreacted acetic anhydride and causes the insoluble aspirin to precipitate from the solution.
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A student expected 1g of product in the aspirin lab but ended up with 1.65g. Why could this be?
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It could be excess water or excess ethyl acetate.
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What does it mean in the aspirin lab when you test your finished product with Iron (III) Cl and get a purple result?
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It indicates the presence of phenols which means some salicylic acid remains and the product is not pure aspirin.
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Why does old aspirin smell like vinegar?
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The acetylsalicylic acid mixes with the humid air (H2O) and converts to salicylic acid + acetic acid (vinegar).
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Why are the aspirin crystals rinsed with ethanol / ethyl acetate?
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To dehydrate the product.
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What physical attribute can we use to differentiate carboxylic acids from esters?
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Carboxylic acids smell sour and esters smell sweet.
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What is esterification?
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Reaction of a carboxylic acid with an alcohol yielding an ester.
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Are carboxylic acids soluble in water?
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Only slightly.
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How do carboxylic acids react with bases?
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They react to form water soluble salts.
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What is saponification?
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The base-promoted decomposition of esters to yield an alcohol and a salt of carboxylic acid.
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What type of reaction occurs and what product results when an ester is treated with an aqueous acid?
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A hydrolysis reaction. Hydrolysis of an ester yields a carboxylic acid and an alcohol - the reverse of esterification.
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What is the general composition of a soap?
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The sodium salt of a fatty acid.
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How could you separate the mixture of two solids: an aromatic hydrocarbon and benzoic acid?
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- Add NaOH to convert the benzoic acid to a soluble salt
- Filter the aromatic hydrocarbon to isolate - Reacidify the filtrate, recreating the benzoic acid - Filter to isolate |
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A component of a molecule that gives rise to stereoisomerism. There is often a carbon atom attached to four distinct groups.
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stereocenter
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Isomers that are not constitutional isomers. These differ in the spatial arrangement of atoms.
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stereoisomer
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Molecules without a plane of symmetry.
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chiral molecules
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Molecules with a plane of symmetry, optically inactive, that do not rotate plane-polarized light.
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achiral molecules
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Stereoisomers that are not enantiomers.
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diastereomers
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Stereoisomers that are non-superimposable mirror images.
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enantiomers
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A compound that contains multiple stereocenters but is achiral due to an internal plane of symmetry.
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meso
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In general, for a given stereocenter, an ___-numbered exchange of groups leads to the mirror image of that center; an ___-numbered exchange of groups leads back to the original system.
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In general, for a given stereocenter, an odd-numbered exchange of groups leads to the mirror image of that center; an even-numbered exchange of groups leads back to the original system.
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What are the three classifications of carbohydrates?
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- monosaccharide
- disaccharide - polysaccharide |
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Define carbohydrate:
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They are polyhydroxy aldehydes or ketones or compounds that yield polyhydroxy aldehydes or ketones upon hydrolysis.
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Explain the structure of a monosaccharide:
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A cyclic structure containing hemiacetal groups.
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Explain the structures of di- and polysaccharides:
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Cyclic structures containing functional groups such as hydroxyl groups, acetal groups, and hemiacetal groups.
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What is the difference between a reducing and non-reducing carbohydrate?
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Reducing carbohydrates have a hemiacetal functional group and can reduce solutions such as Fehling's reagent. Non-reducing carbohydrates have acetals as the functional group and must undergo hydrolysis to break the glycosidic links to create hemiacetals (reducing ends).
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How many monosaccharide units does a starch have?
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2,000 - 10,000
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What is an emulsion?
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A solution where one liquid is dispersed in the form of finely suspended particles or droplets in another liquid.
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How does soap work?
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The nonpolar hydrophobic end attaches to the greasy dirt while the polar hydrophilic end dissolves into the water, allowing the entire mess to be washed away.
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Why does soap become ineffective in hard water?
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The Ca2+ and/or Mg2+ in hard water replaces the Na+ atom on the soap molecule rendering it ineffective.
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What happens if soap is put in an acidic solution?
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It is converted to free fatty acids and loses its cleansing properties.
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What is "salting out"?
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A saturated NaCl solution is added to the soap mixture. This increases the density of the aqueous solution, allowing the soap to more easily float out of the solution.
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How could you reduce the basicity of your soap?
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- Rinse with more water to wash away extraneous substances
- Add a buffer to the soap |
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Define zwitterion:
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A compound that contains both + and - charges and behaves as both an acid and a base.
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How do you determine the pK value of the carboxylic acid group?
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It is the midpoint of leg 1 on the graph.
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How do you determine the pK of the amino group?
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It is the midpoint of leg 3 on the graph.
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How do you calculate the Ka?
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Ka=10^-pK
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How can zwitterions act as buffers?
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By either adding a H+ or an OH- as needed.
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What function did the HCl serve in the vitamin C titration?
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It acted as a catalyst to speed the reaction up.
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