Term
| what are the two dyes we used and what class of dyes are they? |
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Definition
| orange II and congo red, which are azo dyes |
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Term
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Definition
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Term
| what are the two steps to prepare azo dyes? |
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Definition
1. diazotization
2. coupling |
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Term
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Definition
1. direct dying: synthesizing the dye and then dipping the fabric in it
2. developed dying: synthesizing the dye in the presence of the fabric |
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Term
| how many peaks will show up in the HNMR spectra of 2,2-dimethoxypropane? For acetone/methanol? |
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Definition
| 2,2-dimethoxypropare shows two NMR peaks; acetone and methanol show three combined. |
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Term
| is the hydrolysis of 2,2-dimethoxypropane by HCl exothermic or endothermic? |
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Definition
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Term
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Definition
ROH + HCl ------> RCl + H2O
ZnCl2
primary alcohol: will be clear
secondary: will be clear for a bit, then cloudy
tertiary: will be cloudy |
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Term
| if upon performing the chromic acid test the substance turns from orange to green, what are the three possibilities for your unknown? |
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Definition
| could be a primary alcohol, a secondary alcohol, or an aldehyde |
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Term
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Definition
| tells primary alcohols from secondary alcohols (secondaries form a precipitate very quickly) |
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Term
| 2,4-dinitrophenylhydrazone test |
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Definition
| aldehydes and ketones yield a bright yellow precipitate |
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Term
| if you do a 2,4-dinitrophenylhydrazone test and get a yellow precipitate, what are the two tests you can then do to determine what species you have? |
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Definition
| 2,4-dinitrophenylhydrazone test is positive for both aldehydes and ketones. The Tollens test and the chromic acid test both only test positive for aldehydes. |
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Term
| Tollens Test (include equation) |
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Definition
you get a silver precipitate from an aldehyde, but not a ketone.
2Ag(NH3)2OH + aldehyde ---> 2Ag + carboxylic acid + NH4+ + H2O + NH3 |
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Term
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Definition
| identifies methyl ketones (yellow precipitate) |
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Term
| what is an example of a chain-growth polymer? |
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Definition
| polyethylene (CH2CH2CH2CH2etc) |
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Term
| nylon, polyeurothane, and polyester are examples of what kind of polymer formation? |
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Definition
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Term
| what solvent is used for the formation of nylon? What by-product is formed? |
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Definition
solvent: hexane
by-product: HCl |
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Term
| what do you combine with pthalic anhydride if you want linear polyester? cross-linked polyester? |
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Definition
linear polyester: pthalic anhydride + ethylene glycol
cross-linked polyester: pthalic anhydride + glycerol |
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Term
| what do you use to form polyurethane? |
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Definition
| a diisocyanate and a polyol |
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Term
| in hydrogen bonding using NMR, when will acac predominate? |
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Definition
| when you are using a POLAR solvent |
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Term
| what is a dielectric constant? |
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Definition
| a measure of the ability of a substance to insulate charges from each other; will be higher in more polar species |
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Term
| what was the most polar deuterated solvent we used in the keto-enol equilibrium experiment? |
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Definition
| deuterated dimethyl sulfoxide |
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Term
| what is the equilibrium constant for the keto-enol experiment? |
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Definition
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Term
| in the keto-enol experiment, what will result in a HIGHER Ke? |
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Definition
| a less polar solvent; this will shift equilibrium toward the enol species and raise enol/keto |
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Term
| in the keto-enol experiment, what will be the result of using a solvent with a high dielectric constant? |
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Definition
| there will be more of the keto form; therefore the Ke (equilibrium constant) will be smaller |
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Term
| how do you tell keto from enol in NMR? |
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Definition
| keto has two peaks; enol has four |
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Term
| in the keto-enol experiment, what is the only solvent without TMS already added? |
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Definition
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Term
| what is the pattern of a higher mole fraction in the keto-enol experiment? |
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Definition
| having a higher mole fraction means there's more solvent, which means the solution is less polar, which means more of the enol form, which means the Ke is higher |
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Term
| when a ketone is used for mixed aldol condensation, what is the reaction called? |
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Definition
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Term
| describe the reaction used in crossed aldol condensation |
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Definition
benzaldehyde + acetone ---------> (E,E)-dibenzalacetone
NaOH |
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Term
| what is the equation for absorbance? |
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Definition
| A = Ecl where E is the molar extinction coefficient/molar absorbtivity |
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Term
| why is (E,E) dibenzalacetone more stable than (E,Z) or (Z,Z)? |
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Definition
1. the p orbitals on its sp2 carbons overlap
2. steric reasons
3. it also stacks well with itself |
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Term
| in the order of (Z,Z) --> (E,Z) --> (E,E), show the direction of increase of melting point, wavelength, molar absorbtivity, and Hf |
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Definition
melting point: ----------->
wavelength: ---------->
molar absorbtivity: ----------->
Hf: <--------- |
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Term
| to measure the absorbance of dibenzalacetone, dissolve it in... |
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Definition
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Term
| in the measurement of bibenzalacetone, what is the spectrophotometer we used? |
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Definition
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Term
| what are the y-axis and x-axis of the 40 UV/VIS spectrophotometer? |
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Definition
y-axis: absorbance
x-axis: wavelength |
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Term
| what are the unites for the A and wavelength of the crossed aldol condensation? |
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Definition
| A has no units; wavelength is in cm |
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Term
| describe the synthesis of aspirin |
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Definition
| use salicylic acid and anhydride; react with phosphoric acid (H3PO4) |
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Term
| how do you detect the presence of salicylic acid? |
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Definition
|
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Term
| what do we use as the NMR solvent for aspirin? |
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Definition
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Term
| what solvent did we use for aspirin TLC? |
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Definition
| 1:1 ratio of methylene chloride and ethanol |
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Term
| if the Rf is smaller, that means the mobile phase was... |
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Definition
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Term
| why is water added to the aspirin after synthesis? |
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Definition
| to decompose any unreacted anhydride |
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Term
| why did we recrystallize the aspirin? |
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Definition
| to prevent hydrolysis back into salicylic acid |
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Term
| is the pinacol rearrangement exothermic or endothermic? |
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Definition
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Term
| what method to we use in molecular modelling? |
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Definition
| the semi-empirical method |
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Term
| describe the synthesis of orange II dye |
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Definition
| sulfanic acid with NaNO2 and HCl makes a diazonium salt; adding 2-napthol and NaOH gives you sulfonic dye |
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Term
| what is the purpose of the SO3H group on sulfanic acid? |
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Definition
| it makes the dye water soluble and interacts with ionic charges |
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Term
| what happens when you reduce sulfonic dye with Na2SO4? |
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Definition
| it breaks the N=N bond, reducing the conjugation and fading the orange color |
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Term
| what is the difference between direct dying and developed dying? |
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Definition
direct dying: synthesizing the dye first, then dying the fabric
developed dying: synethsizing the dye WHILE dying the fabric |
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Term
| describe the structure of cotton |
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Definition
| made of cellulose, which is mostly carbon rings linked with oxygen - not too great with ionic charges/dying |
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Term
| why do wool and silk bond well with sulfanic dye? |
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Definition
| the polar SO3- of the sulfanic dye binds ionically with the charged parts of the R-groups of the wool and cotton polypeptides |
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Term
| describe the dying affinity of nylon |
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Definition
| it has some polar character, so it binds dye better than cotton but not as well as wool/silk |
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Term
| congo red will appear _________ in acidic solution and _________ in basic |
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Definition
| blue in acid, red in base |
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