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Chem 28 > Lecture 1: Introduction to Analytical Chemistry > Flashcards

Lecture 1: Introduction to Analytical Chemistry Flashcards

1
Q

TWO TYPES OF DIGITS

A

EXACT AND INEXACT

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2
Q
  • NUMBERS NOT MEASURED USING INSTRUMENTS
  • INCLUDES DEFINED NUMBERS
  • INFINITE NUMBER OF SFS
  • DOESN’T AFFECT ACCURACY/PRECISION OF CALCULATIONS OR PRECISION
A

EXACT NUMBERS

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3
Q

WHAT TYPE OF DIGITS ARE THESE?

  1. 1 FOOT = 12 INCHES
  2. 100 YRS IN A CENTURY
A

EXACT NUMBERS

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4
Q
  • NUMBERS WHICH ARE MEASUREMENTS MADE WITH INSTRUMENTS

- WITH INHERENT UNCERTAINTY FROM THE INSTRUMENTS

A

INEXACT NUMBERS

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5
Q

INDICATES THE PROBABLE UNCERTAINTY IN AN EXPERIMENTAL MEASUREMENT

A

SIGNIFICANT FIGURES

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6
Q

ALL THE DIGITS THAT ARE “CERTAIN” + FIRST UNKNOWN DIGIT

A

SIGNIFICANT FIGURES

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7
Q

TRUE OR FALSE:

NON ZERO DIGITS ARE ALWAYS SIGNIFICANT

A

TRUE

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8
Q

TRUE OR FALSE: ZERO IS SIGNIFICANT WHEN IT IS BETWEEN 2 NON-ZERO DIGITS

A

TRUE

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9
Q

TRUE OR FALSE:

THE FINAL/TRAILING ZEROS OF A NUMBER IS SIGNIFICANT

A

FALSE

- ONLY FOR THE DECIMAL PORTION

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10
Q

TRUE OR FALSE:

ZEROS BETWEEN DECIMAL POINT AND NON-ZERO DIGITS ARE SIGNIFICANT

A

FALSE

- THEY SERVE AS PLACEHOLDERS ONLY

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11
Q

ADDITION/SUBTRACTION

- ROUND ANSWER TO ______ NO. OF ______ OF ANY OF THE GIVEN NUMBERS

A

LEAST, DECIMAL PLACES

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12
Q

MULTIPLICATION/DIVISION

- ROUND ANSWER TO _______ NO. OF _______ OF ANY OF THE GIVEN NUMBERS

A

LEAST, SFS

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13
Q

SF IN LOGARITHM

A

NO. OF SFS IN THE ORIGINAL NUMBER = NO. OF SFS TO THE RIGHT OF DECIMAL POINT

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14
Q

SF IN ANTILOGARITHM

A

NO. OF SFS OF ANSWER = NO. OF SIGNIFICANT DECIMAL PLACES IN GIVEN

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15
Q

SHOULD ROUNDING OFF BE DONE DURING CALCULATIONS?

A

NO. AT THE END ONLY.

- ROUND OFF ONLY FINAL RESULT. PRELIMINARY ROUNDING OFF OF RESULTS IS DISCOURAGED

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16
Q

WHY SOULD ROUNDING OFF BE MINIMIZED DURING CALCULATIONS?

A

TO MINIMIZE DEVIATION OF FINAL ANSWER FROM CORRECT VALUE

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17
Q 
INDICATE NO. OF SFS
A. 0.0050
B. 3000
C. 1.5 x 10^-2
D. 500.0
E. 1.5050 x 10^3
A 
A. 2
B. 1
C. 2
D. 4
E. 5
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18
Q 
ROUND OFF ACCORDING TO SPECIFIED NO. OF SFS
A. 15.9994 (4)
B. 15.515 (4)
C. 254.5 (3)
D. 14.5001 (2)
A

A. 16.00
B. 15.52
C. 255
D. 15

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19
Q

PERFORM OPERATION. OBSERVE CORRECT NO. OF SFS

15.12 mL x 19.25 mL x 2.07 mL

A

602.4942 –> 602 (3 SF)

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20
Q

PERFORM OPERATION. OBSERVE CORRECT NO. OF SFS

4.5 in - 1.258 in

A

3,242 –> 3.2 (1 DECIMAL PLACE ONLY)

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21
Q

(2.34 - 1.2) x 0.105

A

1.1 x 0.105 = 0.1155 –> 0.12 (2 SF)

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22
Q

WHAT ARE THE WAYS OF EXPRESSING SOLUTION CONCENTRATION?

A

MMPPN

MOLARITY
MOLALITY
PERCENT COMPOSITION
PARTS PER MILLION
NORMALITY
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23
Q

MOLES OF SOLUTE DIVIDED BY LITERS OF SOLUTION

A

MOLARITY (M)

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24
Q

FORMULA AND UNITS OF MOLARITY

A

FORMULA: M = moles solute/L solution

UNITS: mol/L or M

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25
Q

MOLES OF SOLUTE DIVIDED BY KILOGRAMS OF SOLVENT

A

MOLALITY (m)

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26
Q

FORMULA AND UNITS OF MOLALITY

A

FORMULA: m = moles solute/kg solvent

UNIT: mol/kg or m

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27
Q

THREE TYPES OF PERCENT COMPOSITION

A

A. %w/w - % weight per weight
B. %v/v - % volume per volume
C. %w/v - %weight per volume

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28
Q

FORMULA FOR %w/w

A

%w/w = (g solute/g solution) x 100%

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29
Q

FORMULA FOR %v/v

A

%v/v = (mL solute/mL solution) x 100%

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30
Q

FORMULA FOR %w/v

A

%w/v = (g solute/mL solution) x 100%

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31
Q

FORMULA FOR ppm

A

EITHER %w/w or %w/v

ppm = (g solute/g solution) x 10^6

ppm = (g solute/mL solution) x 10^6

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32
Q

FORMULA FOR ppb

A

EITHER %w/w or %w/v

ppm = (g solute/g solution) x 10^9

ppm = (g solute/mL solution) x 10^

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33
Q

NUMBER OF EQUIVALENTS OF SOLUTE IN 1L SOLUTION

A

NORMALITY (N)

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34
Q

FORMULA FOR NORMALITY

A

N = no. eq solute/L solution

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35
Q

DESCRIBE THE AMOUNT OF A CHEMICAL SPECIES JUST LIKE MOLES

A

EQUIVALENTS (eq) OR MILLIEQUIVALENTS (meq)

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36
Q

MOLARITY: NORMALITY = MOLES: _______

A

EQUIVALENTS

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37
Q

MOLARITY: ______ = MOLES: EQUIVALENTS

A

NORMALITY

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38
Q

THIS IS THE DEFINITION OF THE “EQUIVALENT” AT THE EQUIVALENCE POINT OF ANY TITRATION

A

NO. OF eq ANALYTE PRESENT = NO. OF eq REAGENT ADDED

OR

NO. OF meq ANALYTE PRESENT = NO. OF meq REAGENT ADDED

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39
Q

WHY IS THERE NO NEED TO DERIVE THE STOICHIOMETRY BETWEEN THE ANALYTE AND TITRANT?

A

BECAUSE WE JUST HAVE TO CORRECTLY DEFINE THE eq OR meq FOR EACH TYPE OF REACTING SPECIES

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40
Q

THE AMOUNT OF SUBSTANCE CONTAINED IN ONE EQUIVALENT CAN VARY DEPENDING ON THE _________

A

TYPE OF REACTION

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41
Q

FORMULA FOR CALCULATING THE NUMBER OF EQUIVALENTS PRESENT IN A SAMPLE

A

no. eq = mass in g/EW

EW = EQUIVALENT WEIGHT OF ANALYTE

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42
Q

WHAT IS EW?

A

EQUIVALENT WEIGHT OF THE ANALYTE

43
Q

FORMULA FOR CALCULATING THE EW

A

EW = FW/n

FW = FORMULA WEIGHT OF ANALYTE
n = FACTOR THAT DEPENDS ON TYPE OF CHEMICAL REACTION
44
Q

THIS IS THE FACTOR THAT DEPENDS ON THE TYPE OF CHEMICAL REACTION BETWEEN ANALYTE AND TITRANT

A

factor n

45
Q

THIS CAN BE USED TO CONVERT MOLARITY TO NORMALITY AND VICE VERSA

A

factor n

46
Q

HOW IS THE RELATIONSHIP OF M AND N EXPRESSED IN AN EQUATION

A

N = n x M

47
Q

TYPES OF CHEMICAL REACTION BETWEEN THE ANALYTE AND THE TITRANT

A

CARP

COMPLEXATION
ACID-BASE (NEUTRALIZATION)
REDOX
PRECIPITATION

48
Q

FOR A NEUTRALIZATION REACTION, WHAT IS n?

A

NUMBER OF H+ IONS THAT AN ACID DONATES OR THAT A BASE ACCEPTS

49
Q

FOR A PRECIPITATION REACTION, WHAT IS n?

A

CHARGE OF CATION OR ANION PARTICIPATING IN THE REACTION

50
Q

FOR A COMPLEXATION REACTION, WHAT IS n?

A

NUMBER OF ELECTRON PAIRS A METAL ACCEPTS OR A LIGAND DONATES

51
Q

FOR A REDOX REACTION, WHAT IS n?

A

NUMBER OF ELECTRONS RELEASED BY THE REDUCING AGENT OR ACCEPTED BY THE OXIDIZING AGENT

52
Q

GIVEN REACTION:
H2SO4 + 2NH3 -> (2NH4)+ + (SO4)2-

type of reaction = ?
n of acid = ?
n of base = ?

A

type of reaction = ACID-BASE / NEUTRALIZATION

n of acid (H2SO4) = 2
DONATES 2 PROTONS

n of base (NH3) = 1
ACCEPTS 1 PROTON

53
Q

GIVEN REACTION:
Pb2+ + 2I- -> PbI2

type of reaction = ?
n of Pb2+ = ?
n of I- = ?

A

type of reaction = PRECIPITATION

n of Pb2+ = 2
CHARGE OF PB2+ = 2

n of I- = 1
CHARGE OF I- = 1

54
Q

GIVEN REACTION:
Ag+ + 2NH3 -> Ag(NH3)2+

type of reaction = ?
n of metal = ?
n of ligand = ?

A

type of reaction = COMPLEXATION

n of metal (Ag+) = 2
n of ligand (NH3) = 1

55
Q

GIVEN REACTION:
2Fe3+ + Sn2+ -> Sn4+ + 2Fe2+

type of reaction = ?
RA = ?
OA = ?
n of RA = ?
n of OA = ?
A

type of reaction = REDOX

RA = Sn2+
OA = Fe3+

n of RA = 2
n of OA = 1

56
Q

THESE ARE IMPORTANT IN SOLUTION PREPARATION

A

DILUTIONA ND ALIQUOT FACTORS

57
Q

IN SOLUTION PREPARATION, KEEP IN MIND WHICH BETWEEN ______ AND ______ IS HELD CONSTANT FOR EACH PROCESS

A

NUMBER OF MOLES, CONCENTRATION

58
Q

IN DILUTION, ______ IS KEPT CONSTANT

A

NUMBER OF MOLES

59
Q

IN GETTING ALIQUOTS, ______ IS KEPT CONSTANT

A

CONCENTRATION

60
Q

IMPORTANT EQUATIONS IN DILUTION

A

M x V = n = constant

M1V1 = M2V2 = M3V3

61
Q

IN GETTING ALIQUOTS, WHY IS THE NUMBER OF MOLES NOT HELD CONSTANT?

A

GETTING ALIQUOTS = GETTING A PORTION OF THE SOLUTION –> THIS HAS LESS MOLES THAN THE WHOLE

62
Q

WHAT ARE THE STEPS IN CHEMICAL ANALYSIS?

A

SOPAC

  1. SELECT METHOD (appropriate and reliable)
  2. OBTAIN GROSS SAMPLE FROM BULK
  3. PROCESS SAMPLE
  4. ANALYSIS
  5. CALCULATIONS AND REPORT DATA
63
Q

IN SELECTING AN ANALYTICAL METHOD, IT MUST BE FIT FOR THE ______

A

PURPOSE

64
Q

DIFFERENT SOURCES OF ANALYTICAL METHODS

A

BIPS

  1. BOOKS (published by professional organizations_
  2. IN-HOUSE
  3. PUBLISHED (in open scientific literature)
  4. STANDARD ORGANIZATIONS
65
Q

FACTORS IN CHOOSING A METHOD

A

CASES SLAPS

  1. COST
  2. ANALYSIS TIME
  3. SAFETY
  4. EQUIPMENT REQUIRED
  5. SAMPLE SIZE
  6. SENSITIVITY
  7. LIMIT OF DETECTION
  8. ACCURACY
  9. PRECISION
  10. SPECIFICITY AND SELECTIVIITY
66
Q

FACTORS IN CHOOSING A METHOD:

FUNDING SUPPORT

A

COST

67
Q

FACTORS IN CHOOSING A METHOD:

CLOSENESS TO TRUE VALUE (ABS AND REL ERROR)

A

ACCURACY

68
Q

FACTORS IN CHOOSING A METHOD:

SMALLEST CONCENTRATION THAT CAN BE DETECTED

A

LIMIT OF DETECTION

69
Q

FACTORS IN CHOOSING A METHOD:

CLOSENESS TO INDIVIDUAL DATA

A

PRECISION

70
Q

THESE ARE USED TO EVALUATE PRECISION OF DATA

A

s, RSD, CONFIDENCE INTERVAL

71
Q

FACTORS IN CHOOSING A METHOD:

TO MINIMIZE EFFORT AND COST

A

ANALYSIS TIME

72
Q

FACTORS IN CHOOSING A METHOD:

ABILITY TO DISCRIMINATE BETWEEN ANALYTE WITH INTERFERENCES PRESENT IN THE SAMPLE MATRIX

A

SPECIFICITY AND SELECTIVITY

73
Q

FACTORS IN CHOOSING A METHOD:

CAPABILITY OF METHOD TO RESPOND RELIABLY AND MEASURABLY TO CHANGES IN ANALYTE CONCENTRATIONS

A

SENSITIVITY

74
Q

FACTORS IN CHOOSING A METHOD:

COST, AVAILABILITY

A

EQUIPMENT REQUIRED

75
Q

FACTORS IN CHOOSING A METHOD:

SINCE SOME METHODS REQUIRE LARGER AMOUNT OF SAMPLE THAN OTHERS

A

SAMPLE SIZE

76
Q

FACTORS IN CHOOSING A METHOD:

FOR THE WELFARE OF RESEARCHER/EXPERIMENTER

A

SAFETY

77
Q

PROCESS OF SELECTING PORTION OF MATERIAL TO REPRESENT OR PROVIDE INFO ABOUT A LARGER BODY OF MATERIAL

A

SAMPLING

78
Q

LARGER BODY OF A MATERIAL WHERE A REPRESENTATIVE SAMPLE IS TAKEN

A

BULK/BULK SAMPLE

79
Q

PROCESS TO OBTAIN REQUIRED SAMPLE SIZE APPROPRIATE FOR ANALYSIS

A

SAMPLING

80
Q

THIS IS DONE IN SAMPLING TO SIMPLIFY THE ANALYSIS

A

REDUCING SIZE OF BULK SAMPLE TO A HOMOGENOUS LAB SAMPLE

81
Q

BULK SAMPLE –> GROSS SAMPLE –> LAB SAMPLE

A

SAMPLING

82
Q

REPRESENTATIVE OF THE BULK

A

SAMPLE

83
Q

MUST BE TAKEN INTO ACCOUNT WHEN SAMPLING

A

STATE OF PARENT MATERIAL

84
Q

TWO TYPES OF SAMPLES

A

HHDS

HOMOGENOUS
HETEROGENOUS
DYNAMIC
STATIC

85
Q

TYPE OF SAMPLE:

BREAKFAST CEREAL

A

HETEROGENOUS

86
Q

TYPE OF SAMPLE:

VEGETABLE OIL AT 400C

A

HOMOGENOUS

87
Q

TYPE OF SAMPLE WHEREIN THE COMPOSITION OF PARENT MATERIAL IS PERMANENT WRT SPACE AND TIME

A

STATIC

88
Q

TYPE OF SAMPLE WHEREIN PARENT MATERIAL IS CHANGING WITH TIME

A

DYNAMIC

89
Q

TYPE OF SAMPLE:

WAREHOUSE STOCK OF FOOD, OIL IN A DRUM

A

STATIC

90
Q

TYPE OF SAMPLE:

BLOOD, RIVER WATETR

A

DYNAMIC

91
Q

TYPE OF SAMPLE WHEREIN REMOVAL OF A PORTION OF PARENT MATERIAL AT ANY INSTANT REPRESENTS ONLY A SNAPSHOT OF THAT MOMENT IN TIME AND IN THAT PARTICULAR LOCATION

A

DYNAMIC

92
Q

TYPES OF SAMPLING

A

RANDOM AND SELECTIVE

93
Q

TYPES OF RANDOM SAMPLING

A

SSS

SIMPLE
STRATIFIED
SYSTEMATIC

94
Q

TYPE OF SAMPLING WHEREIN ANY SAMPLE HAS AN EQUAL CHANCE OF SELECTION

A

SIMPLE

95
Q

TYPE OF SAMPLING WHEREIN LOT IS DIVIDED AND RANDOM SAMPLES ARE COLLECTED FROM EACH DIVISION

A

STRATIFIED

96
Q

TYPE OF SAMPLING WHEREIN RANDOM WITHIN TARGET GROUPS

A

STRATIFIED

97
Q

TYPE OF SAMPLING THAT IS BEST WHEN WHOLE POPULATION IS AVAILABLE

A

SIMPLE

98
Q

TYPE OF SAMPLING THAT IS BEST WHEN THERE ARE SUBGROUPS TO INVESTIGATE

EX: DEMOGRAPHIC GROUPINGS

A

STRATIFIED

99
Q

TYPE OF SAMPLING WHEREIN FIRST SAMPLE IS SELECTED AT RANDOM THEN SUBSEQUENT SAMPLES ARE TAKEN ACCORDING TO A PREVIOUSLY ARRANGED INTERVAL (EVERY nth PERSON)

A

SYSTEMATIC

100
Q

TYPE OF SAMPLING THAT IS BEST WHEN A STREAM OF REPRESENTATIVE SAMPLES ARE AVAILABLE

A

SYSTEMATIC

101
Q

TYPE OF SAMPLING:

RAFFLE DRAW

A

SIMPLE

102
Q

TYPE OF SAMPLING:

REGIONAL RAFFLE DRAWS

A

STRATIFIED

103
Q

TYPE OF SAMPLING:

TAKE EVERY 50TH BOTTLE IN A PRODUCTION LINE FOR QUALITY CONTROL ANALYSIS

A

SYSTEMATIC

Chem 28 (2 decks)

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