Organic Chemistry 8

Question 1

reverse of esterification reaction called

Answer 1

hydrolysis reaction

Question 2

reaction for making soap

Answer 2

base hydrolysis of an ester

Question 3

base hydrolysis of an ester , what does the ester react with?

Answer 3

bases such as KOH or NaOH

Question 4

base hydrolysis of an ester 2 products

Answer 4

alcohol and a salt of a carboxylic acid

Question 5

base hydrolysis of an ester which product is the soap

Answer 5

salt of the carboxylic acid

Question 6

result of base hydrolysis of an ester can also be called

Answer 6

saponification

Question 7

base hydrolysis of an ester condition

Answer 7

heat

Question 8

base hydrolysis of an ester fat used

Answer 8

glyceryl tristearate

Question 9

glyceryl tristearate where is it found

Answer 9

animal fat

Question 10

alcohol produced

Answer 10

propan-1,2,3-triol or glycerol

Question 11

soap produced

Answer 11

potassium/sodium stearate

Question 12

why is soap suitable for cleaning skin?

Answer 12

large non-polar part and smaller ionic part, oils dissolve in large non-polar part and ionic salts from skin dissolve in ionic functional group

Question 13

why is soap suitable for cleaning skin? write equation

Answer 13

C17H35 COO- Na+

Question 14

name of apparatus

Answer 14

reflux apparatus

Question 15

should the reflux have a stopper or be open

Answer 15

open

Question 16

where does the water go in

Answer 16

the bottom of the liebig condenser

Question 17

reaction vessel

Answer 17

round-bottomed flask

Question 18

why does water go in the bottom of the liebig condenser

Answer 18

should be filled against gravity so that there are no air bubbles so that there are no pressure imbalances

Question 19

what is in the reaction vessel at the beginning

Answer 19

glyceryl tristearate
sodium hydroxide
ethanol
ant-bumping granules

Question 20

which is the limiting reactant

Answer 20

glyceryl tristearate

Question 21

function of ethanol

Answer 21

solvent for the lard

Question 22

function of anti-bumping granules

Answer 22

absorb heat from the reaction thus preventing violent shaking of the apparatus

Question 23

why is this done under refluc?

Answer 23

this ensures that there is time for the complete saponification reaction without losing any volatile material

Question 24

how long do you let it go on for?

Answer 24

30 minutes

Question 25

what ends up on the side of the glass and why is it a problem

Answer 25

residue which contains soap - will reduce the yield of soap

Question 26

how can you remove the residue from the sides?

Answer 26

wash down with a minimum of hot water

Question 27

too much hot water

Answer 27

will reduce the yield of soap

Question 28

after 30 minutes

Answer 28

heat removed and allowed to cool slightly

Question 29

what is in the reaction vessel after the 30 minutes

Answer 29

``` ethanol sodium hydroxide (excess) water propan-1,2,3-triol anti-bumping granules sodium stearate ```

Question 30

how to isolate soap

Answer 30

distillation

Question 31

what do you distill off

Answer 31

2/3 of the ethanol

Question 32

why do you distill off 2/3 of the ethanol

Answer 32

to isolate the soap as some soap may be dissolved in the ethanol and the soap would not precipitate fully to get a maximum yield (more concentrate soap mixture)

Question 33

after distillation

Answer 33

hot mixture allowed to cool slightly

Question 34

how and where do you put solution after distillation

Answer 34

decant quickly into a concentrated salt solution (brine)

Question 35

why brine

Answer 35

soap is insoluble and precipitates out of solution

Question 36

what happens when solution has been decanted

Answer 36

ant-bumping granules removed

Question 37

after decanted into brine

Answer 37

filtered

Question 38

what is used to filter

Answer 38

a buchner funnel

Question 39

after filtration and why

Answer 39

soap washed many times with cold water to remove sodium hydroxide clinging to soap as it is caustic

Question 40

after soap is washed

Answer 40

allow to dry on filter paper or in a dessicator

Question 41

actual yield of soap

Answer 41

weigh it

Question 42

theoretical yield of soap

Answer 42

found from ration 1:3 of glyceryl tristearate (limiting reactant)

Question 43

Mr of glyceryl tristearate

Answer 43

890

Question 44

simple word equation for base hydrolysis of an ester

Answer 44

ester + base -> alcohol + salt of carboxylic acid