Organic Chemistry Lab Fall Midterm

Unit 8: definition of IR spectroscopy

Analytical technique that uses infrared radiation to identify substances by analyzing their molecular vibrations

Unit 5: what was the purpose of refueling the residue from the ethanol step?

release pigments

unit 5: list all the components in the vial after week one of the experiment

pet ether, B carotene, and lycopene

unit 5: why do two layers of liquid form in the separator funnel in the step after the reflux?

water and pet ether are immiscible/have opposite polarity

unit 5: what do each of the two layers of liquid contain?

top: pet ether, B carotene, lycopene

bottom: water, NaCl, acetone, and solid impurities

unit 5: how many pigments were in each eluded fraction? and what is your evidence?

one or two

evidence: TLC

unit 5: how do you know you were successful separating B carotene and lycopene?

there were fractioning containing only B carotene and only lycopene

unit 5: how do you know you were successful separating b carotene and lycopene from vegetable paste?

during extraction there were multiple layers observed: top orange layer and bottom clear layer

unit 5: why was anhydrous sodium sulfate added?

to remove water

unit 7: definition of miscible

separation of miscible liquids based on differences in bp

unit 7: what is the main difference between fractional and simple distillation?

fractionating column 

unit 7: what’s the difference between distillation and chromatography?

distillation: based on bp

column: based on relative polarity

unit 7: what is the chemistry definition of miscible?

mutually soluble in all proportions

unit 7: what difference in physical properties was used to isolate the pigments from the paste?

the pigments were nonpolar

unit 7: what difference in physical properties was used to separate the pigments from each other?

B relatively less polar than L

unit 7: which is more polar? B carotene or lycopene?

B carotene

unit 7: which was eluted first from the column? 

B carotene because its less polar and could travel down the polar siclia gel