Org Chem Lab Techniques

Question 1

One of most common lab procedure ysed when isolating or purifying a product.

Answer 1

Extraction

Question 2

An organic solvent is used to extract the organic product from inorganic substances of the mixture

Answer 2

Liquid to liquid extraction

Question 3

Most important method of purifying nonvolatile organic solids

Answer 3

Recrystalization

Question 4

T or F
The solvent used for recrystalization should
-dissolbe desired substance at high temp and impurities or not at all
-do not react with the desired substance
- non flammable volatile and inexpensive

Answer 4

True

Question 5

This uses fluted filter paper and a stemless funnel

Answer 5

Hot gravity filtration

Question 6

This has a larger surface are compare to ordinary conical filter paper

Answer 6

Fluted filter paper

Question 7

Using a ____ avoids premature crystallization

Answer 7

Stemless funnel

Question 8

This filtration used filter flask and buchner funnel which is made of porcelain, glass or plastic

Answer 8

Suction filtration

Question 9

On top of the buchner funnel is acylinder with a fritted glass disc or ____ where the filter paper is placed

Answer 9

Perforated plate

Question 10

After recrystalization, a pure, nonionic crystalline organic compound usually had a sharp and characteristic _____ range

Answer 10

Melting point

Question 11

The traditional approach to melting point determination is the use of

Answer 11

Thiele tube

Question 12

This is a type of mp analyzer used round microscope cover slips that contain the samples and placed on a heating block. This is also called hot stage and comes with a spotlight to observe sample

Answer 12

Fisher-Johns apparatus

Question 13

This uses a heated metal block and also uses capillary packed samples which can be observed through a lense on the front

Answer 13

Mel temp apparatus

Question 14

This is the same as water bath except it uses silicone or mineral oils in order to enable temperature hotter than the boiling point of water.

Answer 14

Oil bath

Question 15

This oil bath can be heated 250°C

Answer 15

Silicon oil bath

Question 16

This oil bath can be heated up to 300°C. Since this is composed of mixtures of long chain alkanes and so is combustible

Answer 16

Mineral oil bath

Question 17

This is also heated on a hotplate and can be used to heat solutions greater than 250°C. This can also be heatedup to moderate tempered insude thin aluminum foil pie dishes but should NOT be used at high temperature as aluminum will then oxidize causing the thin foil to disintegrate

Answer 17

Sand baths

Question 18

A type of glass used in distillation flask

Answer 18

Borosilicate glass

Question 19

This is one of the potential of a solution where bubbles vigorously erupt from superheated areas of solution but gas bubbles have not yet formes due to lack of nucleation site

Answer 19

Bumping

Question 20

Boiling chips or boiling stones are usually_____

Answer 20

Silicon carbide

Question 21

They contain trapped air that bubbles out as a loquid is heated and have a large surface area that can act as a nuclearion site for formation of solvent bubbles

Answer 21

Boiling chips or stones

Question 22

They work same as boiling chips and also used for smooth boiling but they are plunged into a somvent of solution

Answer 22

Boiling sticks or wood splints

Question 23

This type of fractional column has the largest surface are making it least capable of separating close boiling components but have the hughest recovery making it optimal choice if a separation is not particularly difficult

Answer 23

Vigreux column

Question 24

This column have intermediate surface areas and their effectiveness can depend on how tightly the wool is pacjed in the column. This column also cannot be used with corrosive vapors like containing acids

Answer 24

Steel wool column

Question 25

Have a high surface area and are a good choice for separation components however beads will suffer the greatest loss of materials

Answer 25

Glass beads column

Question 26

In this type of distillation, the separating liquids boiling points must be less than 150°C from a nonvolatile impurities

Answer 26

Simple distillation

Question 27

This type of set up can be used in distilling or separating liquids having a bpiling point greater then 150°C from non volatile impurities

Answer 27

Vacuum distillation

Question 28

We use this set up when separating liquid mixtures solibles with each other that boil at greater than 25°C from each other

Answer 28

Fractional Distillation

Question 29

We use this kind of set up if we isolate the liquid compiunds that are insoluble or slightly soluble in water at all temperature

Answer 29

Steam distillation

Question 30

This method is used to determine the number of components in a mixture, identify of components, purity of a sampleand to monitor the progress of the reaction

Answer 30

TLC

Question 31

The component in this phase is called stationary (solid _____)

Answer 31

Silica gel

Question 32

This is the liquid solvent in TLC

Answer 32

Mobile phase

Question 33

The different components of the samole have different _______ this these components will move different distance from the original spot location

Answer 33

Polarities

Question 34

This is equal to the distance travled by the component divided by the distance travled by the solvent

Answer 34

Retardation or retention factor Rf