Exam Study: practice Flashcards
List four types of information that can be found in a compounds material safety data sheet
Flammability
Chemical identification
Health hazards
Reactivity data
Physical data
First aid info
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?
CHEMICAL HYGEINE PLAN
Lab coats, safety goggles and gloves are collectively known as PPE. What does PPE stand for?
Personal Protective Equipment
Write the proper name for each piece of equipment labeled in the distillation
apparatus pictured below.
Starting top left, going clockwise:
Claisen adapter
Distillation head
Water condenser
Vacuum take-off adapter
Graduated cylinder
Distilling flask / round-bottom flask
In which of the following solvents will 4-methylbenzoic acid have the highest solubility?
Dichloromethane
Ethanol
Toluene
Ethanol
Polar, h-bond donor AND acceptor.
Rank the following solvents with respect to polarity (1 being most polar):
Toluene
Hexane
Ethyl acetate
Ethyl ether
Acetone
1 - Acetone
2 - Ethyl acetate
3 - Ethyl ether
4 - Toluene
5 - Hexane
Give two reasons why acetone is a good solvent to use for rinsing out glassware as part of the cleaning process
- It has a low boiling point and therefore evaporates easily
- Its electronegative oxygen atom creates a polarity, so acetone easily attracts many compounds
- It’s miscible with water
How do you repurify sulfanilamide if it has been dropped on the floor?
- Recrystallization: dissolve in boiling ethanol, cool, and do vacuum filtration
- Column chromatography
How do you find % recovery?
% yield / theoretical yield
Is a sulfanilamide sample 161.6-163.2C pure if MP = 165-165C?
No - The range is narrow - melting range is broadened if sample is impure
Lowered range likely due to uncalibrated apparatus
How do you calculate Rf?
Distance traveled / solvent front
Remember sig figs!
Are more or less polar solvents closer to solvent front?
Less, they’re less held back by stationary phase
What (e.g. polarity) elutes first in column chromatography?
Least polar
List in order of polarity: alcohols, cabonyls, alkenes
alkenes < carbonyls < alcohols
How does solvent polarity affect compound location in TLC?
???
What do phase diagrams show?
Composition x temp with melting point below on graph and boiling point above
How do you find vapor composition in a phase diagram above liquid?
Keeping temperature constant, see where the gas curve is at
Why is determining the response factor necessary for gas chromatography?
The GC detector isn’t equally sensitive to everything, so you have to correct output to a per-mole basis
What is an azeotrope?
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
How do you figure out # plates in fractionating column?
Figure out the # of times it evaporates (straight lines) before it hits 100%
What is the order of polarity between ethers, carbonyls, alcohols, halogens, and alkanes?
alcohol > carbonyl > ether > halogen > alkane
Will low BP or high BP compounds have longer retention time in GC?
Higher boiling point. More polar = more held back
