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CHEM 354 > EXAM 1 (EXP 2, 3, 6, 8) > Flashcards

EXAM 1 (EXP 2, 3, 6, 8) Flashcards

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1
Q

What are some distinct types of information that can be found in a compound’s material safety data sheet (MSDS)?

A
  1. chemical identification (name and CAS
    number)
  2. Hazardous ingredients, if a mixture of
    chemicals
  3. Physical data (such as bp or mp)
  4. Flammability and explosion danger
  5. Reactivity data
  6. Health hazards (toxicity)
  7. First aid and emergency information
  8. Measures to control exposure (PPE)
  9. Spill handling procedures
  10. Special procedures, waste disposal
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2
Q

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?

A

Chemical Hygiene Plan

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3
Q

Which will travel fastest in TLC- a polar or non-polar compound?

A

non-polar compound will travel up fastest

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4
Q

Which will elute first in column chromatography - a polar or non-polar compound?

A

most non-polar compound will elute first

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5
Q

Will your Rf values change if you replace the TLC solvent with pure acetone instead of DCM?

A

Rf values will be larger, but the order would stay the same as if you were using DCM as a solvent

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6
Q

Why do you determine the response factor for each component in GC?

A

Because the detector does not detect the components equally

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7
Q

What is an azeotrope?

A

A mixture of liquids which are unable to be separated by distillation

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8
Q

While performing column chromatography, a colored band shows excessive tailing as it passes through the column. How can you fix this problem?

A

Increase the polarity of the solvent constantly while eluting

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9
Q

What does TLC stand for?

A

Thin-Layer Chromatography

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10
Q

What are 2 scenarios where good separation can be achieved by only simple distillation

A
  1. the BP differences are large (over 100 degrees C)
  2. less than 10% of impurity is present in the mixture
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11
Q

Put the IMFs in order of strongest to weakest: Hydrogen Bonding, electrostatic attraction, van der Waals, Dipole-Dipole, Ion-Dipole

A

Electrostatic > Ion-dipole > Hydrogen Bonding > Dipole-Dipole > van der Waals

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12
Q

Explain how Chromatography separates molecules

A

separates molecules based on how strongly they absorb to the solid phase or how quickly it absorbs in liquid (based on polarity and IMFs)

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13
Q

What does the Rf value tell you?

A

How quickly a compound moves in reference to other compounds in the mixture

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14
Q

How do you determine if your compound is pure in TLC?

A

There will be only one spot

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15
Q

What can TLC tell you?

A

compound composition/purity as well as the progress of a reaction

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16
Q

What is the elutant (or eluate) in column chromatography?

A

The solutes or materials to be separated

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17
Q

What is the eluent in column chromatography?

A

the solvent

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18
Q

Explain how you can correct the following TLC:
a 2 compound mixture gave only one spot with an Rf=0.95. Solvent was acetone

A

Decrease the polarity of the solvent

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19
Q

Explain how you can correct the following TLC:
a 2 compound mixture gave only one spot with an Rf=0.05

A

Increase the polarity of the solvent

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20
Q

Explain how you can correct the following Column Chromatography:
the substances you are trying to purify stop moving down the column

A

Increase the polarity of the solvent

21
Q

How do you choose a good solvent for crystallization?

A

High solubility at high temps and low solubility at low temps

22
Q

What happens if your solvent’s boiling point is higher than the melting point of the solid?

A

“oil out” - the solid melts before it dissolves

23
Q

What should you do if you get a precipitate during the crystallization cooling process?

A

Reheat and add more solvent, start again!

24
Q

Can you ever get 100% recovery from crystallization?
Why? (2 reasons)

A

No- there is always impurity present in the starting compound which will cause a loss of some mass as you remove the impurity.
Some of your compound will always remain dissolved in the solvent.

25
Q

When do you use the semi-microscale method for crystallization?

A

When the weight of the solid to be crystallized is more than 0.1 g

26
Q

When do you use the microscale method for crystallization?

A

When the weight of the solid to be crystallized is less than 0.1 g

27
Q

What is “mother liquor”?

A

the solution that remains after a crystallization

28
Q

name this piece of equipment:

A

Conical Vial

29
Q

name this piece of equipment:

A

Craig Tube

30
Q

name this piece of equipment:

A

multipurpose adapter

31
Q

name this piece of equipment:

A

Centrifuge Tube

32
Q

name this piece of equipment:

A

Erlenmeyer Flask

33
Q

name this piece of equipment:

A

Spin Bar

34
Q

name this piece of equipment:

A

Spin Vane

35
Q

name this piece of equipment:

A

Thin-walled vial

36
Q

name this piece of equipment:

A

Claisen head adapter

37
Q

name this piece of equipment:

A

Water-cooled reflux condenser

38
Q

name this piece of equipment:

A

distillation head

39
Q

name this piece of equipment:

A

Vacuum take-off adapter

40
Q

name this piece of equipment:

A

Round-Bottom Flask

41
Q

name this piece of equipment:

A

thermometer adapter

42
Q

name this piece of equipment:

A

Air reflux condenser

43
Q

name this piece of equipment:

A

Hirsch funnel

44
Q

name this piece of equipment:

A

Filter Flask

45
Q

name this piece of equipment:

A

Separatory Funnel

46
Q

name this piece of equipment:

A

Büchner Funnel

47
Q

How do you calculate weight (g)?

A

density (g/mL) x volume (mL)

48
Q

What does the retention time tell you from GC data?

A

How long the component satyed in the GC column

higher BP = higher retention time

49
Q

What does the peak area tell you from GC data?

A

Used to determine the relative amount of different components

CHEM 354 (2 decks)

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