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orgchem lab > Isolation of Caffeine from Dried Tea Leaves > Flashcards

Isolation of Caffeine from Dried Tea Leaves Flashcards

(59 cards)

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1
Q

It is an alkaloid and has base characteristics

A

Caffeine

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2
Q

Caffeine has the ____________, a framework that plays an important role in living systems

A

Purine Ring System

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3
Q

Caffeine is also known as:

A

1,3,7-trimethylxanthine

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4
Q

Caffeine is odorless, has a bitter taste and is ______________

A

Highly Soluble in Hot Water

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5
Q

What is the boiling point of Caffeine? (in celsius)

A

178°C

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6
Q

What is the melting point of Caffeine?

A

235-238°C

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7
Q

Caffeine acts as a ________ - are medications designed to increase the amount of water and salt expelled from the body as urine

A

Diuretic

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8
Q

Caffeine also ________ metabolism

A

stimulates

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9
Q

Caffeine also contributes to an increase in ____________ levels in the blood

A

Dopamine

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10
Q

Caffeine is also a ________ present in tea, coffee, cocoa, cola nuts and beverages.

A

stimulant

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11
Q

small doses of this chemical (blank) can** increase alertness** and reduce drowsiness and fatigue.

A

50-200 mg

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12
Q

Caffeine also affects blood circulation because the heart is stimulated and blood vessels are _____________ (vasodilation)

A

Relaxed

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13
Q

Large doses of caffeine (of over ________) can result in insomnia, restlessness, headaches, and muscle tremors.

A

over 200 mg

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13
Q

Continued, heavy use of caffeine may bring on (blank)

A

Physical Dependence

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14
Q

It is consists primarily of cellulose (the principal structural material of all plant cells)

A

Composition of Tea Leaves

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15
Q

Cellulose is insoluble in water, thus, can be separated from caffeine by ______________

A

Hot Water Extraction

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16
Q

It is a colored polyphenolic compounds of high molecular weight (500-3000 g/mol) that have acidic behavior.

A

Tannins

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17
Q

Tannins are ________ complex substances.

A

Water Soluble

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18
Q

It is responsible for astringency, color, and some flavor in tea.

A

Tannins

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19
Q

TRUE OR FALSE:

As much as 5% by weight of the leaf material in tea
plants consists of caffeine.

A

TRUE

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20
Q

It allows soluble components to be removed from solids using a solvent.

A

Solid-Liquid Extraction

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21
Q

Application of this unit operation include obtaining oil from oil seeds or leaching of metal salts from ores.

A

Solid-Liquid Extraction

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22
Q

They are readily soluble in hot water and is separated from tea leaves.

A

Caffeine and Tannins

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23
Q

It involves using a **liquid solvent to remove a liquid component ** from a liquid mixture.

Study These Flashcards
A

Liquid-Liquid Extraction

24
It is known as **partitioning **
Liquid-Liquid Extraction
25
**TRUE OR FALSE: ** In Liquid-Liquid Extraction, the component dissolves preferably in the solvent.
True
26
What are the applications of Liquid-Liquid Extraction?
* Removal of Vitamins from Aqueous Solutions * Aromatic Compounds from Crude Oil Fractions *(in chemical and mining industries and in the downstream recovery of fermentation products)
27
TRUE OR FALSE: Frequently, one of the solvents is **water** or an aqueous mixture **(aqueous phase)** and the other is a non-polar organic liquid **(organic phase).**
TRUE
28
Liquid-Liquid Extraction comprises of two steps:
Mixing phase and phase separation
29
The solubility of caffeine in water is _______ ?
2g/100 g of cold water
30
The solubility of caffeine in dichloromethane is ______ ?
14g/100g
31
A procedure by which two liquids with **different boiling points** can be separated.
Distillation
32
Powerful technique for separating the component substance from a miscible fluid mixture by means of selective** evaporation** and **condensation. **
Distillation
33
What are the parts of Separatory Funnel?
* Stopper * Teflon Stopcock * Separatory Funnel Body
34
**PROCEDURE (Solid-Liquid Extraction) ** 1. What labels do you need to write in a 125 mL Erlenmeyer Flask?
Flask 1: Aqueous Layer Flask 2: Organic Layer
35
2. What measurements of the chemicals you need to place in a 250mL beaker with a watch glass?
* 10.0 grams of dried tea leaves * 6.25 grams of sodium carbonate * some boiling chips
36
3. Pour ________ mL of Distilled Water into the beaker.
87.5
37
4. Turn hotplate to ____. Heat the mixture to boiling for 10 minutes. (Start time when mixture starts to boil).
300°C
38
5. ________ the liquid into a 250-mL Erlenmeyer Flask. Make sure that no solid particles will be included in the supernatant liquid.
Decant
39
6. Cool the __________ to room temperature.
Aqueous Extract
40
PROCEDURE (Liquid-Liquid Extraction) 1. Pour the cooled aqueous extract into a 125mL separatory funnel in the _______
fumehood
41
2. Extract the solution with ________ of __________ . Mix by inverting the mixture in a rocking motion repeatedly. Take care not to shake the funnel too vigorously. (5 shakes by 5 sets)
15 mL of CH2CL2
42
3. How many minutes you should let it stand the Separatory Funnel until the layers separate?
About 5 minutes
43
4. Drain the CH2CL2 layer into a 125mL Erlenmeyer Flask #?
Flask #1
44
5. What you should do next after draining the CH2CL2 in the Erlenmeyer flask?
* Repeat steps 2 and 3 using another 15mL of CH2CL2 * Combine the two CH2CL2 layers.
45
6. Add a small amount of __________ to the pooled extract, and swirl the mixture for a few seconds.
Sodium Sulfate
46
PROCEDURE (Distillation): 1. Filter the dichloromethane extract through a _________ into a ____________
cotton plug; 250mL distillation flask.
47
2. What you should do after filtering the dichloromethane?
Assemble a distillation set-up
48
6. ________ the evaporating dish to room temperature and weigh.
Cool
48
5. Evaporate the dichloromethane to dryness over a ___________
Hot water bath
49
3. Distill the dichloromethane and collect about ________. Take note of the _______
50mL; BP Range
49
4. Transfer the remaining solution to a _____________
pre-weighted evaporated dish.
50
7. Collect the ____________ of caffeine into a labeled vial and submit to your lab instructor
greenish-white crystals.
51
What is the solubility of caffeine in water?
2.17g/100mL water at 25C
52
What is the solubility of caffeine in a chloroform?
18.18g/100mL chloroform at 25C
53
The __________ is an expression of the relative preference of the solute for the solvents.
Distribution coefficient
54
What is the equation of a substance in each layer?
C1/C2 = Kd
55
What does C1 stands for?
Concentration of solute in layer 1
56
What does C2 stand for?
Concentration of solute in layer 2

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