Analytical Chemistry Exam 1

Front 1

General Steps in a Chemical Analysis

Back 1

Sampling, Sample Preparation, Chemical Analysis, Calibration Curves, Interpreting Results

Front 2

Aliquot

Back 2

Portion

Front 3

Analyte

Back 3

thing being analyzed

Front 4

aqueous

Back 4

mixed with water

Front 5

calibration curve

Back 5

graph of detection response as a function of analyte concentration

Front 6

decant

Back 6

pour off

Front 7

heterogeneous

Back 7

composition differs from place to place

Front 8

homogeneous

Back 8

composition is the same everywhere

Front 9

interference

Back 9

causes response to test to differ from the

accurate result

Front 10

masking

Back 10

changing a reaction so that there is no

interference

Front 11

qualitative analysis

Back 11

identifying what is present

Front 12

quantitative analysis

Back 12

identifying how much is present

Front 13

quantitative transfer

Back 13

a complete transfer

Front 14

micro-

Back 14

10^-6

Front 15

solute

Back 15

minor species

Front 16

solvent

Back 16

major species

Front 17

electrolyte

Back 17

substance that dissociates into ions in solution

Front 18

formal concentration

Back 18

molarity of a strong electrolyte

Front 19

formula mass

Back 19

molecular mass of a strong electrolyte

Front 20

molarity

Back 20

moles/liter

Front 21

molality

Back 21

moles/kg solvent

Front 22

possible weighing errors

Back 22

touching with hand, drafts, vibrations, object not centered

Front 23

buret

Back 23

glass tube manufactured to deliver

Front 24

transfer pipet

Back 24

suck up with rubber bulb; to deliver

Front 25

micropipet

Back 25

automated; to deliver

Front 26

dessiccator

Back 26

closed chamber containing a drying agent with an airtight lid

Front 27

systematic error

Back 27

flaw in equipment or design of experiment; reproducible

Front 28

random error

Back 28

uncontrolled variables in measurement; cannot be corrected

Front 29

absolute uncertainty

Back 29

margin of uncertainty associated with a measurement

Front 30

relative uncertainty

Back 30

compares size of absolute uncertainty with size of associated measurement

Front 31

real rule for sig figs

Back 31

the first digit of uncertainty is the last significant digit in the answer.

Front 32

Gaussian Distribution

Back 32

ideal smooth calibration curve (bell curve)

Front 33

T-test

Back 33

comparing one mean value with another to test if they are significantly different from one another

Front 34

F-test

Back 34

comapares 2 standard deviations

Front 35

Grubbs-test

Back 35

tests if an outlier is significantly different from the rest of the data

Front 36

Q-Test

Back 36

tests for bad data: gap/range

Front 37

Gravimetric Analysis

Back 37

mass of product is used to compute quantity of original analyte

Front 38

nucleation

Back 38

molecules join together to form aggregates

Front 39

particle growth

Back 39

molecules form a crystal

Front 40

supersaturated solution

Back 40

more solute is present than there should be; when a precipitate forms

Front 41

digestion

Back 41

promotes slow recrystallization of the

precipitate

Front 42

masking

Back 42

prevent impurities from reacting with precipitant

Front 43

ignition

Back 43

strong heating

Front 44

coprecipitation

Back 44

impurity is precipitated along with desired product

Front 45

thermogravimetric analysis

Back 45

substance is heated and its mass is measures as a function of temperature

Front 46

combustion analysis

Back 46

used to determine amounts of C and H in organic compounds burned in excess O2

Front 47

Pyrolysis

Back 47

thermally decomposed substance in the

absence of added O2