Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

20 chemistry for the biosciences > L10 - spectroscopy > Flashcards

L10 - spectroscopy Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

define spectroscopy

A

use of electromagnetic radiation to characterise matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

shorter wavelength =

A

higher frequency

higher energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

longer wavelength =

A

lower frequency

lower energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is resonance spectroscopy

A

spectroscopy to detect the movements within atoms and molecules
the electromagnetic frequency used to detect this has to match the motion its detecting
eg electron spin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

define constructive interference

A

two of the same frequencies in phase can combine to produce bigger frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

define destructive interference

A

two of the same frequencies out of phase will cancel eachother out (180° out of phase)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

define chromophore

A

‘system’ that can absorb electromagnetic radiation (typically in visible / uv range)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what do spectrometers do?

A

show the wavelengths absorbed/transmitted by a sample

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is UV-Vis absorbance spec

A

using UV light to detect how much of a molecule is present in a sample (molecule has to absorb UV/ visible light)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

explain process of UV - Vis absorbance spec

A
  1. liquid sample containing substance of interest put into cuvette
  2. cuvette put into spectrophotometer and light shone through at certain frequencies
  3. beer lambert law used to calculate how much light absorbed
  4. absorbance used to calculate conc of material in sample
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

biological uses of UV - vis absorbance spec

A

measure concs of proteins in sample

some contain ring structures where the double bonds absorb certain wavelengths that can be detected by uv’-vis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is infrared spec

A

the frequencies used interact with frequencies of bond vibrations to show what bonds are present in an unknown sample in order to identify it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how does infrared spec wavelengths compare to uv/visible

A

longer wavelengths (lower freq)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

uses of infrared spec

A

identifying what substance is present in a sample by the bonds present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

limitations of infrared spec

A
  1. bond interactions eg H bonds in water can interfere

2. peaks may overlap especially with macromolecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what phase is used in UV-Vis spec

A

liquid

17
Q

explain process of fluoresence spec

A
  1. light shone at cuvette containing fluorophore and detector placed 90° from it
  2. fluorophore absorbs light and emits back out at a different frequency
18
Q

what is a fluorophore

A

substance that can absorb light and fluoresce

19
Q

explain the excitation emission phenomenon

A

a fluorophore can absorb light at one frequency then emit it at a different frequency

20
Q

is the emission or excitation wavelength longer?

A

emission

21
Q

is the emission intensity as high as the excitation?

A

no
the emission is not as intense as the excitation
(not 100% of absorbed is emitted)
wave height of emission is smaller

22
Q

define quantum yield

A

efficiency of light emitted

difference between emission height and excitation height

23
Q

what is stokes shift?

A

difference between excitation wavelength and emission wavelength

24
Q

applications of fluorescence spec

A
  1. detect single molecules
25
Q

what does a fluorophore typically contain

A

aromatic compounds (alternating double bonds)

26
Q

what is NMR spec

A

nuclear magnetic resonance

gives info on proton environments

27
Q

how does NMR spec work?

A

radio waves interact with the nuclear spin of nuclei

nuclei spin to different extent depending on surrounding molecules

28
Q

uses of NMR spec

A
  1. identifying compounds

2. determining 3D structure

29
Q

limitations of NMR

A

not very sensitive, many molecules needed to be able to detect

30
Q

advantages of NMR spec

A
  1. atomic resolution - individual peaks can be assigned to individual atoms helping identify 3D structure of molecule
31
Q

what is mass spec

A

spec where ion ‘fragments’ are formed from molecules and their masses are measured as peaks
the value of peak is the fragments mr

32
Q

what is X ray crystallography

A

uses diffraction patterns of crystalline solids exposed to x ray radiation to infer their 3D shapes

33
Q

what wavelength is used in NMR

A

radiowaves

20 chemistry for the biosciences (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions