Brainscape's Knowledge GenomeTM

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


See full index

Analytical Chemistry > Instrumental Methods of Analysis ❗️ > Flashcards

Instrumental Methods of Analysis ❗️ Flashcards

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

What are the three instrumental methods of analysis?

A
  • spectroscopy
  • electrochemistry
  • chromatography
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is analytical chemistry divided into?

A

1) Chemical methods
2) Physical methods

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

What are the different chemical methods?

A

1) gravimetric method
2) volumetric method

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

What are instrumental methods about?

A

determining chemical compositions of compounds

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

What is classical analysis?

A

signal depends on the chemical properties of the sample:
- a reagent reacts completely with the analyte
- the relationship is measured between the analyte and titrant

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

What is instrumental analysis?

A

a physical property of the sample is measured:
- electrical potential
- pH
- etc.

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

What are the types of instrumental (physical) methods?

A

1) optical methods
2) chromatographic methodds
3) electrochemical methods

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

Why are the advantages of instrumental methods?

A

1) speed
2) sensitivity
3) selectivity (accurate in presence of many different components)
4) reproducibility
5) small sample requirements

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

Why are the disadvantages of instrumental methods?

A

1) cost
2) complexity
3) maintenance (eg. breaking of lab equipment, clogging of equipment, etc.)

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

What is an analytical technique?

A

Scientific phenomenon giving information on the composition of substances.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is an analytical method?

A

specific application of technique used to solve an analytical problem.

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

What is a procedure?

A

instructions formilated to carry out a method (lists out steps to be followed for analysis).

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

What is a protocol?

A

The most specific description of a method.
- detailed directions must be followed without exception

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

What is a basic block diagram for instrumental measurements?

A

stimulus (energy) –> system under study –> response (analytical information)

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

What is absorption?

A

Process by which the energy of light (in the form of photons) is transferred to the atom or molecule raising them from the ground state to the excited state.

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

When does emission/radiation happen?

A

When molecules/atoms fall back down to lower energy levels, emitting radiation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is fluorescence?

A

absorbed energy is rapidly lost to the surroundings by collisions within the system and relax back to the ground state.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is Beer-Lambert-Bouguer law?

A

relates the attentuation of light to the properties of the material through which the light is passing.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the equation of Beer-Lambert-Bouguer law?

A

A=Elc
A- absorbance
E- energy
l- optical path length
c- concetration of chemical species in mol/L

absorbance = path length
absorbance = sample concentration
= direc. prop

20
Q

What is electromagnetic radiation?

A

form of energy that is transmitted through space at enourmous velocities.
electric field, magentic field, and electromagnetic wave are all at 90 * angles

21
Q

What is wavelength?

A

distance from crest units (maximum points/minimum points)

22
Q

What is frequency?

A

number of waves per second (Hz, Hertz)

23
Q

What is wave number?

A

the number of waves per unit length

24
Q

What is power? What else is it called?

A
  • energy per unit time,
  • also known as intensity
25
Q

What is paramagnetic spectroscopy?

A

microwave technique based on the splitting electronic fields in a magnetic field.
- used to determine structures of samples containing unpaired electrons

26
Q

What is a different name for “infrared spectroscopy”?

A

“molecular fingerprint”
- used to identify materials,
- quantify the number of absorbing molecules

27
Q

What is x-ray spectroscopy?

A
  • excitation of inner electrons of atoms, which may be seen as x-ray absorption.
  • an x-ray fluorescence emission spectrum may be used
28
Q

What is electrochemistry?

A
  • concered with the interelation of electrical and chemical effects

eg. measurement of electrical quantities, current, potential, their relationship and parameters.

29
Q

What is an electric current?

A

flow of charge through a medium
- moving electrons in a conductor
- carrid by ions in electrolyte
- carried by electrons and ions in plasma

30
Q

What is potential?

A
  • quantitative description of the driving force behind an electrochemical reaction
31
Q

What is an electrochemical cell?

A

A cell consisting of two electronic conductors (electrodes) dipped into a solution (containing ions and electrolytes).

32
Q

How does a pH sensor work?

A

based on an electric potential difference (build up of h+ ions within the pH meter)

33
Q

What is potentiomentry?

A

measurement of electric potential

34
Q

What are the two types of indicator electrodes?

A

1) metal electrodes (develop an electric potential in response to a redox reaction at the metal surface).
2) ion selective electrode (bind one type of ion to a membrane to generate an electric potential).

35
Q

How is electric potential generated?

A

by the build up of H+ ions on one side of the glass meter.

36
Q

What are the advantages of pH meters?

A

1) potentail is not affected by its presence of oxidizing or reducing agents
2) wide pH range
3) responds fast and functions well in physiological systems

37
Q

What is chromatography?

A

technique for seperating mixtures into their components by their distinctive mechanisms of interations (reactions) of the solute (mobile phase) with the stationary phase. Differences occur due to differences in:
- size
- charge
- shape

38
Q

What type of gel is used?

A

silica gel

39
Q

What are the two phases in chromatography?

A

1) stationary phase (solvent)
2) mobile phase (column packing material)

40
Q

What is chromatography used for?

A
  • analyzing
  • identifing
  • purifing
  • quantifing
41
Q

What are the two types of chromatography?

A

1) column
2) planar

42
Q

What is column chromatography?

A
  • glass tube filled with silica gel
  • fresh solvent is set on top

solvents seperate due to their mobile phases.

43
Q

What is planar chromatography?

A
  • stationary phase is placed on a flat plate and the mobile phase travels across it by gravity or capillary.
  • paper chromatography
44
Q

What is dissociation?

A

a substance dividing into ions and cations

45
Q

What are strong electrolytes

A

Analytical Chemistry (12 decks)

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