EXERCISE 4

Question 1

SCIENTIFIC NAME

Tea

Answer 1

Camellia sinensis L.

Question 2

FAMILY NAME

Tea

Answer 2

Theaceae

Question 3

• an evergreen shrub common to East Asia used to produce tea
• contains theophylline and theobromine, polyphenols, flavonoids, epigallocatechin gallate, and other catechins

Answer 3

TEA

Question 4

Tea contains

Answer 4

theophylline and theobromine

Question 5

tea, theophylline and theobromine are collectively known as

Answer 5

methylxanthines

Question 6

• Tea consist mostly of ____
• water-insoluble polymer of glucose
• structural polysaccharide in plants

Answer 6

cellulose

Question 7

• phenolic compounds
• have hydroxyl group directly bonded to an aromatic ring

Answer 7

tannnins

Question 8

components of tea

Answer 8

caffeine
tannins
chlorophyll
cellulose

Question 9

types of tea is classifiede based on

Answer 9

level of oxidation

Question 10

TYPES OF TEA

• allowed to wither
• fully oxidized
• dark brown / black leaves
• hhigher caffeine content (50-65%

Answer 10

BLACK TEA

Question 11

TYPES OF TEA

• aged; with natural sweet note
• compressed into shaped
• includes pure tea

Answer 11

DARK TEA

Question 12

TYPES OF TEA

• partially oxidized
• caffeine content in between black and green teas
• taste & aroma like or fresh flowers

Answer 12

OOLONG TEA

Question 13

TYPES OF TEA

• slightly withers after picking
• less caffeine content (10-30%)

Answer 13

GREEN TEA

Question 14

TYPES OF TEA

• made uisng youngest shoots
• subtle, complex, naturally sweet

Answer 14

WHITE TEA

Question 15

TYPES OF TEA

• similar to green tea in appearance and flavor
• go through more oxidation; slower drying period

Answer 15

YELLOW TEA

Question 16

water-soluble materials in the tea leaves are extracted into the ____

Answer 16

hot water

Question 17

caffeine is extracted from the water with ____

Answer 17

dichloromethane

Question 18

solubility of tannins in DCM

Answer 18

slightly soluble

Question 19

why did we use DEIONIZED water

Answer 19

to prevent the ions present in water react to the extraction

Question 20

solubility of caffeine in water ____ as the temperature increases

Answer 20

increases

Question 21

tannins are removed from the organic layer using ____

Answer 21

sodium carbonate

Question 22

tannins react with Na2CO3 to form

Answer 22

tannin salts

Question 23

tannin salts are soluble in ____ and insoluble in ____

Answer 23

soluble - water
insoluble - DCM

Question 24

EXTRACTION OF CAFFEINE FROM TEA

what goes to the aqueous layer

Answer 24

tannin salts

Question 25

# **EXTRACTION OF CAFFEINE FROM TEA** what **retains** in the **organic** layer

Answer 25

caffeine

Question 26

**disadvantage** in converting tannins to their salts

Answer 26

they become **anionic surfactants**

Question 27

# **EXTRACTION OF CAFFEINE FROM TEA** what can **form** upon the conversion of **tannins to anionic surfactants**

Answer 27

emulsion

Question 28

the separatory funnel must not be ____ to avoid forming emulsion

Answer 28

shaken vigorously

Question 29

if emulsion forms, the solution may be ____ using glass rod or addition of ____

Answer 29

stirred slowly more solvent or saturated NaCl

Question 30

# **ISOLATION OF CAFFEINE FROM TEA** PHYSICAL TEST

Answer 30

color - white with a tinge of green odorless amorphous powder

Question 31

# **ISOLATION OF CAFFEINE FROM TEA** Murexide test solution

Answer 31

caffeine + conc. HCl + KClO3