Quant Exam 1

Question 1

identification of what chemical constituents are present in a substance; identity of a compound

Answer 1

qualitative analysis

Question 2

measurement of how much of a chemical substance is present; numerical answers

Answer 2

quantitative analysis

Question 3

step one of chemical analysis

Answer 3

formulating the question - translating general questions into specific questions

Question 4

step two of chemical analysis

Answer 4

selecting analytical procedures - doing a literature search

Question 5

step three of chemical analysis

Answer 5

sampling - selecting representative materials to be measured

Question 6

sample/material composition is the same everywhere

Answer 6

homogeneous

Question 7

sample/material composition differs from region to region

Answer 7

heterogeneous

Question 8

step four of chemical analysis

Answer 8

sample preparation - converting the sample into a suitable form

Question 9

step five of chemical analysis

Answer 9

analysis - repeating measurements, applying different analytical methods

Question 10

step six of chemical analysis

Answer 10

reporting and interpreting

Question 11

step seven of chemical analysis

Answer 11

drawing conclusions

Question 12

substance being measured or detected; also called “measured”

Answer 12

analyte

Question 13

a solution whose composition is known by virtue of the way it was made from a reagent of known purity or by virtue of its reaction with a known quantity of a standard reagent

Answer 13

standard solution

Question 14

liquid remaining above the solid after precipitation

Answer 14

supernatant - also called “supernate”

Question 15

a portion of a substance

Answer 15

aliquot

Question 16

a solution of anything in water

Answer 16

aqueous

Question 17

a suspension of a solid in a solvent

Answer 17

slurry

Question 18

to pour liquid off a solid or, perhaps, a denser liquid; the denser phase is left behind

Answer 18

decant

Question 19

a complete transfer

Answer 19

quantitative transfer

Question 20

a homogenous mixture of two or more substances

Answer 20

solution

Question 21

the minor species in a solution

Answer 21

solute

Question 22

the major species in a solution

Answer 22

solvent

Question 23

formula for molarity (M)

Answer 23

moles solute / liters solution

Question 24

formula for molality (m)

Answer 24

moles solute / kilograms solvent

Question 25

formula for weight percent (% wt)

Answer 25

(grams solute / grams solution) x 100

Question 26

formula for parts per million (ppm)

Answer 26

milligrams solute / liters solution

Question 27

chemical analysis based on weighing the final product

Answer 27

gravimetric analysis

Question 28

Avogadro's Number

Answer 28

6.022 x 10^23

Question 29

formula for dilution

Answer 29

M1V1 = M2V2

Question 30

how close together a set of measurements are; reproducibility

Answer 30

precision

Question 31

how close a measurement is to the true/accepted value; nearness to the truth

Answer 31

accuracy

Question 32

True or False: In addition/subtraction, the number of significant figures is determined by the number with the fewest decimal places.

Answer 32

T

Question 33

True or False: In multiplication/division, the number of significant figures is determined by the factor with the smallest number of digits.

Answer 33

T

Question 34

True or False: In logarithms, the number of significant figures determines the number of decimal places.

Answer 34

T

Question 35

True or False: In antilogs, the number of decimal places determines the number of significant figures.

Answer 35

T

Question 36

a built-in error, consistent, reproducible; in principle, detectable and correctable

Answer 36

systematic error

Question 37

from uncontrollable variables in the measurement; inconsistent error value; can be reduced by repeated trials, but cannot be completely eliminated

Answer 37

random error

Question 38

expresses the margin of uncertainty associated with a measurement

Answer 38

absolute uncertainty

Question 39

compares the sizes of the absolute uncertainty with the size of its associated measurements

Answer 39

relative uncertainty

Question 40

formula for relative uncertainty

Answer 40

absolute uncertainty / magnitude of measurement

Question 41

formula for percent relative uncertainty

Answer 41

(absolute uncertainty / magnitude of measurement) x 100

Question 42

True or False: The number of significant figures in the answer is limited by the number of decimal places in the uncertainty.

Answer 42

T

Question 43

True or False: Random error can be expressed as the standard deviation/standard deviation of the mean/confidence interval.

Answer 43

T

Question 44

True or False: Random errors in arithmetic processes propagate through calculations.

Answer 44

T

Question 45

analyze known samples/certified reference materials, analyze blank samples, use different analytical methods to measure the same quantity, round-robin experiments

Answer 45

ways to detect systematic error

Question 46

formula for relative standard deviation/coefficient of variation

Answer 46

(standard deviation / mean) x 100

Question 47

the absolute value of the highest value minus the lowest value

Answer 47

range

Question 48

True or False: When given an even number of data points, the median is the average of the two middle values.

Answer 48

T

Question 49

True or False: When finding the confidence interval, the degree of freedom is the number of samples minus one.

Answer 49

T

Question 50

EXCEL command for finding the mean

Answer 50

= AVERAGE ( : )

Question 51

EXCEL command for finding the standard deviation

Answer 51

= STDEV ( : )

Question 52

EXCEL command for finding the number of samples

Answer 52

= COUNT ( : )

Question 53

replicate measurements of a sample made by a single analytical technique are compared to an accepted value

Answer 53

case one

Question 54

comparing replicate measurements of a sample measured by two analytical techniques or samples created from two methods measured by one analytical technique

Answer 54

case two

Question 55

multiple samples are measured by two different analytical techniques and the results are compared

Answer 55

case three

Question 56

True or False: For case one, if the known value does not lie within the 95% confidence interval range, then the methods give different results.

Answer 56

T

Question 57

calculated F value < table F value

Answer 57

the difference in standard deviations is not significant; use the s pooled formula to find t

Question 58

calculated F value > table F value

Answer 58

the difference in standard deviations is significant; use the regular t formula

Question 59

calculated t value < table t value

Answer 59

not significantly different mean values

Question 60

calculated t value > table t value

Answer 60

significantly different mean values

Question 61

calculated G value > table G value

Answer 61

questionable value can be discarded

Question 62

calculated G value < table G value

Answer 62

questionable value cannot be discarded

Question 63

True or False: When constructing a standard/calibration curve, the blank value should be subtracted from the measured values.

Answer 63

T - called corrected values

Question 64

True or False: Concentrations of pure solids/liquids/solvents are omitted from the equilibrium constant formula because they are unity.

Answer 64

T

Question 65

reverse reaction equilibrium constant calculation

Answer 65

K' = 1 / K

Question 66

added equilibrium constant calculation

Answer 66

K3 = K1 x K2

Question 67

if a system is subjected to a change/disturbance, the direction in which the system proceeds back to equilibrium will attempt to offset the change

Answer 67

Le Chatelier's Principle

Question 68

Q < K (Le Chatelier's)

Answer 68

the system will shift to the right until Q = K

Question 69

Q > K (Le Chatelier's)

Answer 69

the system will shift to the left until Q = K

Question 70

True or False: Heat is a reactant in an endothermic reaction. (H > 0)

Answer 70

T

Question 71

True or False: Heat is a product in an exothermic reaction. (H < 0)

Answer 71

T

Question 72

(+) G, K < 1

Answer 72

disfavored reaction

Question 73

(-) G, K > 1

Answer 73

favored reaction

Question 74

the equilibrium constant for the reaction in which a solid salt dissolves to give its constituent ions in solution

Answer 74

solubility product

Question 75

Q > Ksp (precipitation)

Answer 75

a precipitate will be formed

Question 76

Q < Ksp (precipitation)

Answer 76

a precipitate will not be formed

Question 77

a salt is less soluble if one of its ions is already present in the solution

Answer 77

common ion effect

Question 78

True or False: A smaller Ksp value means a more soluble salt.

Answer 78

T