Exam Study: practice

Question 1

List four types of information that can be found in a compounds material safety data sheet

Answer 1

Flammability

Chemical identification

Health hazards

Reactivity data

Physical data

First aid info

Question 2

test

What WWU document contains information pertaining to emergency procedures, storage and handling of hazardous materials, proper disposal of hazardous materials (waste), laboratory clothing policy, and methods of training workers?

Answer 2

CHEMICAL HYGEINE PLAN

Question 3

Lab coats, safety goggles and gloves are collectively known as PPE. What does PPE stand for?

Answer 3

Personal Protective Equipment

Question 4

Write the proper name for each piece of equipment labeled in the distillation

apparatus pictured below.

Answer 4

Starting top left, going clockwise:

Claisen adapter

Distillation head

Water condenser

Vacuum take-off adapter

Graduated cylinder

Distilling flask / round-bottom flask

Question 5

In which of the following solvents will 4-methylbenzoic acid have the highest solubility?

Dichloromethane

Ethanol

Toluene

Answer 5

Ethanol

Polar, h-bond donor AND acceptor.

Question 6

Rank the following solvents with respect to polarity (1 being most polar):

Toluene

Hexane

Ethyl acetate

Ethyl ether

Acetone

Answer 6

1 - Acetone

2 - Ethyl acetate

3 - Ethyl ether

4 - Toluene

5 - Hexane

Question 7

Give two reasons why acetone is a good solvent to use for rinsing out glassware as part of the cleaning process

Answer 7

1. It has a low boiling point and therefore evaporates easily
2. Its electronegative oxygen atom creates a polarity, so acetone easily attracts many compounds
3. It’s miscible with water

Question 8

How do you repurify sulfanilamide if it has been dropped on the floor?

Answer 8

1. Recrystallization: dissolve in boiling ethanol, cool, and do vacuum filtration
2. Column chromatography

Question 9

How do you find % recovery?

Answer 9

% yield / theoretical yield

Question 10

Is a sulfanilamide sample 161.6-163.2C pure if MP = 165-165C?

Answer 10

No - The range is narrow - melting range is broadened if sample is impure

Lowered range likely due to uncalibrated apparatus

Question 11

How do you calculate Rf?

Answer 11

Distance traveled / solvent front

Remember sig figs!

Question 12

Are more or less polar solvents closer to solvent front?

Answer 12

Less, they’re less held back by stationary phase

Question 13

What (e.g. polarity) elutes first in column chromatography?

Answer 13

Least polar

Question 14

List in order of polarity: alcohols, cabonyls, alkenes

Answer 14

alkenes < carbonyls < alcohols

Question 15

How does solvent polarity affect compound location in TLC?

Answer 15

???

Question 16

What do phase diagrams show?

Answer 16

Composition x temp with melting point below on graph and boiling point above

Question 17

How do you find vapor composition in a phase diagram above liquid?

Answer 17

Keeping temperature constant, see where the gas curve is at

Question 18

Why is determining the response factor necessary for gas chromatography?

Answer 18

The GC detector isn’t equally sensitive to everything, so you have to correct output to a per-mole basis

Question 19

What is an azeotrope?

Answer 19

Mixture of liquids with a fixed composition that can’t be altered by either simple or fractional distillation

The vapor in equilibrium with its liquid has the same composition

Question 20

How do you figure out # plates in fractionating column?

Answer 20

Figure out the # of times it evaporates (straight lines) before it hits 100%

Question 21

What is the order of polarity between ethers, carbonyls, alcohols, halogens, and alkanes?

Answer 21

alcohol > carbonyl > ether > halogen > alkane

Question 22

Will low BP or high BP compounds have longer retention time in GC?

Answer 22

Higher boiling point. More polar = more held back