quiz#6 Terms

Question 1

types of liquid chromatography:

Answer 1

1) partition
2) ion exchange
3) adsorption
4) size-exclusion

Question 2

partition LC

Answer 2

analytes with varying palarity interact with a nonpolar stationary phase and aqueous mobile phase

Question 3

ion exchange LC

Answer 3

analytes with different charges/charge densities are resolved by a charged stationary pahse

Question 4

adsorption LC

Answer 4

analytes preferentially adsorb to a solid support

Question 5

size-exclusion LC

Answer 5

sort by the size of the molecule (good for macromolecules)

Question 6

t0

Answer 6

time of totally unretained solute; velocity = u0:

H2O

Question 7

t1

Answer 7

time of somewhat retained solute; velocity u1:

MeOH

Question 8

t2

Answer 8

time of somewhat more retained solute; velocity u2:

PrOH

Question 9

retention

Answer 9

a way to describe the length of time an analyte spends on its column relative to its length

Question 10

how is retention reported?

Answer 10

capacity (retention) factor:

k1= (tr-t0)/(t0)

Question 11

selectivity factor

Answer 11

a= KB/KA

Question 12

column performance :

Answer 12

-efficiency= # of theoretical plates AKA # of partitioning opportunities
-HETP=height equivalence to a theoretical plate – H=L/N OR N=L/H
SMALLER HEIGHT = BETTER!

Question 13

Gaussian peaks

Answer 13

N= (tr/s)^2

Question 14

asymmetric peaks

Answer 14

if tailing : assymetric factor/ratio =T=B/A

N=((4.17tr^2)/(1/10w^2))/t+1.25)

Question 15

real samples

Answer 15

implies that some degree of sample preparation will be required

Question 16

neat samples

Answer 16

run as is

Question 17

procedure for sample prep

Answer 17

LOT/Gross–> representive bulk sample–>homogenous lab sample–>aliquots–>analysis

Question 18

BIG 5 Qs?

Answer 18

1- how much sample
2- where to pull withing the sample pool 
3- how much of each sample 
4-how to minimize error in sampling 
5-what kinds of samples to get

Question 19

types of sampling:

Answer 19

1-random
2-biased(judgemental)
3-systematic

Question 20

ways to sample:

Answer 20

• grab
• composite
• in-situ

Question 21

grab

Answer 21

taditional taking a lot

Question 22

composite

Answer 22

multiple grabs from multiple times and then sampled

Question 23

in situ

Answer 23

many tiny pulls from a sampling stream (flow injection analysis)

Question 24

How many samples to collect?

Answer 24

nsamples= (t^2s^2)/e^2

Question 25

direct analysis

Answer 25

get the mass of analyte directly

Question 26

indirect analysis

Answer 26

measure the mass of a related compound and then calculate the mass

Question 27

traditional [analysis]

Answer 27

involves the precipitation of your analyte

Question 28

what is the key to gravimetric analysis?

Answer 28

conservation of mass!

Question 29

what is so great about gravimetric analysis?

Answer 29

it is a definitive technique! aka its not derived, but rather, it uses base SI units

Question 30

steps in GA

Answer 30

``` 1-prepare your sample solution 2-precipitation of the analyte 3-digestion 4-filtration 5-washing 6-drying/ignition 7-weighing 8-calculation ```

Question 31

% analyte (w/w)

Answer 31

(mass of analyte(x)/mass of sample)x100

Question 32

colloids

Answer 32

particle of size 10-100nm

Question 33

electrical double layer

Answer 33

---------- | ++++++

Question 34

gooy chapman layer

Answer 34

``` layer of non-randomness ---------- ++++++ ----+---- ++-++-+ ```

Question 35

zeta potential

Answer 35

the charge that desists* on a colloidal particle

Question 36

types of impurities:

Answer 36

1) inclusions 2) occlusions 3) surface adsorption

Question 37

inclusions

Answer 37

impurities scattered within the crystal lattice

Question 38

occlusions

Answer 38

impurities within the crystal lattice that a large/ clustered

Question 39

surface adsorption

Answer 39

impurities of the surface

Question 40

co-precipitation

Answer 40

this is the generic term for any incorporation of impurities in ion crystal lattice --> inclusions/occlusions/surface adsorption

Question 41

How do you solve surface adsorption?

Answer 41

1- wash your crystals | 2-digestion!- allow precipitate to settle in mother liquor for a long time with slow temperature change

Question 42

Types of Filtration:

Answer 42

1) fast 2) medium 3) slow 4) ashless

Question 43

fast filtration

Answer 43

pore size~20microm

Question 44

medium filtration

Answer 44

pore size~15microm

Question 45

slow filtration

Answer 45

pore size~2microm

Question 46

ashless filtration

Answer 46

leaves you with 0.1mg or less

Question 47

drying

Answer 47

oven@110*C

Question 48

ignition

Answer 48

fire!

Question 49

slurry

Answer 49

mixture of solids and liquids

Question 50

filtrate

Answer 50

what you ore filtering

Question 51

decant

Answer 51

to carefully pour surface liquid

Question 52

creeping

Answer 52

loss of product when it exceeds filter paper

Question 53

hygroscopic

Answer 53

if something is hygroscopic it absorbs water from the atmosphere

Question 54

dessicant

Answer 54

salts that absorb moisture | ----> CaSO4

Question 55

Inorganic analysis:

Answer 55

1. selective reagents | 2. specific reagents

Question 56

selective reagents

Answer 56

targets a small group of ions. | ie. AgNO3

Question 57

specific reagents

Answer 57

target one ion | chelating structure using dimethylgloxine for Ni(+2)

Question 58

TGA

Answer 58

thermal gravimetric analysis