Orgo Lab

Front 1

definition of melting point

Back 1

when solid is in equilibrium with liquid phase

Front 2

eutectic temp

Back 2

actual lower limit of melting point range

Front 3

when looking on graph of melting point and boiling point

Back 3

flat section between mp and bp is due to extra heat breaking intermolecular forces so there is not rise in temp

Front 4

how to tell if compound is pure from mp

Back 4

if the range is less than 2

Front 5

extraction

Back 5

transfer of a solute from one phase to another

ex. coffee powder and hot water = black coffee

2 types: solid liquid

liquid liquid

Front 6

polar bond

Back 6

if two atoms have different electronegativities and are bonded to each other, the bond is said to be polar

Front 7

know polarity of commonly used solvents

Back 7

water most polar

Front 8

recrystallization

Back 8

purification of an impure organic solid

Front 9

choice of solvent

Back 9

solute should be insoluble in room temperature solvent

should be soluble in heated solvent

should crystallize when put in ice following heating

**solvent should have low bp

Front 10

types of impurities

Back 10

insoluble

colored

soluble

Front 11

for insoluble impurities

Back 11

dissolve in solvent and filter off impurities

Front 12

for colored impurities

Back 12

use norite and then do hot filtration, why hot?

Front 13

for soluble impurities

Back 13

recrystallization, dissolve in solvent then let pure compound recrystallize and leave the impurities in mother liquor

Front 14

why do impurities not crystallize out?

Back 14

starting material is mostly the compound we are looking for

solution is concentrated with respect to the desired material but dilute with respect to the impurities

as solvent cools and starts to evaporate, the solution becomes more concentrated in the desired compound and crystals start to form

Front 15

chromatography

Back 15

separation of two or more compounds

one is in still phase, one is in moving phase

diff compounds will have diff solubilities and thus diff absorptions in the two phases

Front 16

adsorption chromatography

Back 16

distribution of solutes between a moving solvent and a solid adsorbent

Front 17

uses of tlc

Back 17

to determine the number of components in a mixture

to determine the identity of substances

to monitor the progress of a reaction

to determine the effectiveness of purification

to determine the conditons for column chromatography

to monitor column chromatography

Front 18

method for tlc

Back 18

solvent moves up plate by capillary action

three interactions on tlc plate

solvent and adsorbent

solvent and compound

adsorbent and compound

ions have highest interaction with adsorbent

Front 19

liquid liquid extraction

Back 19

a solution containing several components is mixed with a second immiscible solvent in order to extract some components into that second solvent

ex. water and oil

Front 20

immiscible

Back 20

does not mix to form a homogenous solution or does not dissolve in first solvent

Front 21

what happens in mixture of water and organic solvent?

Back 21

water: polar

organic: most organic compounds are not very polar so they are not soluble with in water but are soluble in organic solvent

Front 22

distribution coefficient k for c

Back 22

depends upon solubility of C in both solvents

k=concentration of C in S1/ concentration of C in S2

Front 23

when organic compound is mixed with water

Back 23

very little will go into the aqueous layer so not useful

need to do acid base chemistry

Front 24

organic acids and bases used in lab

Back 24

carboxylic acid RCOOH

phenol(aromatic ring) ArOH(weakest)

sulfonic acid RSO3H(strongest)

amines;

primary amines- RNH2

secondary amines-RR'NH

tertiary amines- RR'R"N

anilines- ArNH2

Front 25

organic layer must be dried

Back 25

1. extraction by saturated sodium chloride solution(brine)

2. anhydrous drying agent such as sodium sulfate

Front 26

boiling point

Back 26

defined as the temp at which the vapor pressure equals atmospheric pressure

Front 27

applying increasing amounts of heat to a boiling liquid

Back 27

will not increase the temp but will cause molecules to move from the liquid to the gas phase more quickly

Front 28

distillation

Back 28

the vapor above the mixture is richer in the lower boiling point compound so a series of distillations would create a pure distillate

Front 29

c=0

Back 29

1670-1820

Front 30

c=c stretch

Back 30

1400-1600

Front 31

c=c-h stretch

Back 31

3000

Front 32

oh

Back 32

3200-3600

Front 33

functional group transformation

Back 33

a reaction that changes the functional groups but not the carbon backbone

Front 34

reduction

Back 34

converts ketone to secondary alcohol

use complex metal hydrides

Front 35

oxidation

Back 35

converts secondary alcohol to ketone