6.3 Flashcards Preview

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Flashcards in 6.3 Deck (16)
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1
Q

order ketones+aldehydes, COOHs, alcohols, and esters most to least polar.

A

COOHs, alcohols, ketones+aldehydes, esters

2
Q

how does TLC work?

A

adsorption

3
Q

what state is the stationary phase in TLC?

A

solid

4
Q

in tlc what do you end up with?

A

spots that have moved up the plate

5
Q

in gas chromatography what state is the stationary phase?

A

liquid

6
Q

how does gas chromatography work?

A

relative solubility

7
Q

what does area of peak show in gas chromatography?

A

amount of compound

8
Q

which elements have the shortest retention time in gas chromatography?

A

ones which bind best to the mobile phase.

9
Q

what are the problems with chromatography?

A

similar compounds have similar rf values/retention times

if new compounds are discovered they can’t be identified by comparing value to database.

10
Q

what do you do to be able to know the concentrations of compounds in a sample of gas chromatography?

A

run calibration curves to find area of known concentrations.

11
Q

WHAT IS THE MAIN PEAK ON A MASS SPECTRUM THAT SHOWS THE MR PEAK CALLED

A

THE MOLECULAR ION PEAK

12
Q

WHAT IS THE PEAK THATS ONE AFTER THE MR PEAK CALLED

A

THE M+1 PEAK

13
Q

INSTEAD OF SAYING THE ‘POSITION’ OF NMR PEAKS SAY THE…

A

CHEMICAL SHIFT VALUE

14
Q

WHAT IS THE BASE PEAK IN MASS SPECTROMETRY

A

peak with the greatest (relative) intensity /
peak representing most stable/abundant fragment.
NOT the tallest / biggest / most common peak!!

15
Q

WHY MIGHT THE MOLECULAR ION PEAK NOT BE SEEN ON A MASS SPECTRUM

A

The molecular ion is too unstable / will have been

completely fragmented / may not carry a positive charge. cant say theres too little of it!!

16
Q

when drawing 1H NMR what takes precedence if it has a HC-O environment and an HC-C–O environment?

A

the HC-O one. yeet yah.