Brainscape's Knowledge GenomeTM

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


See full index

CH271—Analytical Chemistry > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

weighing by mass used for…

A

hygroscopic reagents

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

TC

A

to contain

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

TD

A

to deliver

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

sample

A

a representative portion of the material of interest

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

matrix

A

everything in the sample

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

analyte

A

component of interest in the sample

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

trace amount

A

ppb or <0.01%

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

minor component amount

A

ppt or 0.01-1%

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

major component amount

A

pph or >1%

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

defining replicates

A

dividing into aliquots

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

classical wet methods

A

gravimetric
titration

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

instrumental methods

A

separation techniques
spectroscopy
electrochemical

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

classical methods based on…

requires…

A

mass & volume, chemical properties

well-defined rxn stoichiometry

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

instrumental methods based on…

A

signals generated by the analyte with an instrument

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

relationship between signal and concentration in instrumental methods

A

s = kC

k is a constant

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

screening assay

A

determines what exists in a sample

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

information provided by analytical chemistry

A

qualitative

quantitative

chemical identification

structural analysis

property characterization

spatial analysis

time-dependent analysis

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

formal concentration (F)

A

molarity of a strong electrolyte

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

molality

A

moles of solute / kg of solvent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

advantage of molality vs molarity

A

molality does not depent on temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

ppm =

A

(mass substance / mass sample)10^6

mg/L (density @1 g/mL)

mg/kg

μg/g

ng/mg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

ppb =

A

(mass substance / mass sample)10^9

μg/L (density @ 1 g/mL)

μg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

if K > 1….

A

forward rxn is favored

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

define significant figures

A

total number of digits required to write a number in scientific notation without a loss in accuracy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

sig fig rules for addition and subtraction

A

retain same number of decimal places of the number with the fewest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

sig fig rules for multiplication and division

A

number with the greatest uncertainty determines sig figs of the product/quotient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

sig fig rules for logarithm-generated numbers

A

only mantissa is significant, and includes 0 directly after decimal point

the number of sig figs in the number you are taking the log of determines the sig figs in the mantissa

28
Q

analytical concentration

A

does not consider what happens to solute after dissolution

29
Q

species concentration

A

considers chemical changes to solutes

30
Q

specific gravity

A

Dsoln / 1 g/mL = SG (no units)

ratio of denisty of soln to density of H2O @ 4° C

31
Q

purity grades in order from least to greatest purity

A

technical/lab grade

certified ACS & USP, BP, EP, NF, FCC grade

biotech grade

HPLC grade

trace metal grade

32
Q

advantage of using stock soln

A

allows use of larger solute masses - less relative uncertainty

33
Q

define p function

A

pX = -log(X)

34
Q

2 types of error

A

systematic (determinate)

random (indeterminate)

35
Q

detection of systematic error

A

multiple checks with multiple analysts

test a known/blank standard

unusual trends

use of different analytical methods

36
Q

accuracy

A

difference between experimental value and true value

37
Q

precision

A

variation in experimental results

38
Q

absolute error (e) =

A

e = x - μ

x = experimental result
μ = true value

39
Q

relative error (eR) =

A

eR = e/μ

e = absolute error
μ = true value

40
Q

standard deviation describes…

A

precision

41
Q

variance =

A

s^2

42
Q

relative standard deviation (ppt) =

A

RSD = s/x(1000)

43
Q

good, mediocre, bad RSD for classical wet methods

A

good: <4
mediocre: 4-10
bad: >10

44
Q

good RSD for instrumental methods

A

<10

45
Q

__% of measurements lie within +/-1 s of x

A

68

46
Q

___% of measurements lie within +/-2 s of x

A

95

47
Q

why does increasing n make x more accurate?

A

the more values there are, the more likely it is that (+) and (-) random errors cancel one another out

48
Q

relative error =

A

sy / y

49
Q

CI =

A

x ± (ts) / √n

50
Q

CI represents…

A

range around the mean, for a certain confidence level, within which the true value actually lies

51
Q

criteria for suspicion of data points

A

lies >±2 s of x
lies outside CI
seems suspicious based on experience

52
Q

2 tests for outliers

A

Dixon (Q)
Grubbs (Tn)

53
Q

Q =

A

|xo - xn| / xhigh - xlow

xn = nearest value to outlier

54
Q

Tn =

A

|xo - x| / s

55
Q

steps to make a solution

A
  1. transfer measured solute to flask
  2. dissolve in less than desired volume solvent and mix
  3. add more solvent, less than desired volume, and mix
  4. dilute to volume mark
  5. cap, mix and invert many times
56
Q

null hypothesis

A

that there is no difference between your result and the reference value

57
Q

purpose of student’s t test

A

tests accuracy of method with a known standard

58
Q

t = |x - μ| / (s / √n)

μ = reference value

A

student’s t test

59
Q

purpose of F test

A

comparison of precisions between 2 data sets

60
Q

purpose of s pool test

A

comparing the means of two data sets with similar precisions (via the F test)

61
Q

purpose of tcalc test

A

comparing the means of two data sets with dissimilar precisions (via the F test)

62
Q

coefficient correlation (r) describes…

A

how well the data points fit a linear regression

63
Q

if r = 1…
if r is high…
if r is low…

A

r = 1; line fit is perfect

high r; more confidence

low r; more scattering of data points

64
Q

used to determine if a data set is linear

A

residual plot

65
Q

in a residual plot, true linear plots have data…

A

scattered around 0

66
Q

purpose of calibration curve

A

use linear equation of a best-fit line to extrapolate x from y of an experimental value (or vice versa)

CH271—Analytical Chemistry (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions