Chapter 8: Introduction to Analytical Chemistry

Question 1

• science of obtaining, processing, and communicating information about the composition and structure of matter
• art and science of determining what matter is and how much of it exists
• measurement science consisting of a set of powerful ideas and methods that are useful in all fields of science and engineering

Answer 1

Analytical Chemistry

Question 2

Two information required in an analysis

Answer 2

1. Qualitative
2. Quantitative

Question 3

what makes analytical chemistry a vital tool in medical, industrial, government, and academic laboratories throughout the world?

Answer 3

interdisciplinary nature

Question 4

reveals the identity of the elements and compounds in a sample

Answer 4

qualitative analysis

Question 5

indicates the amount of each substance in a sample

Answer 5

quantitative analysis

Question 6

chemical test used for detecting the presence of at least two peptide bonds in a molecule

Answer 6

Biuret test

Question 7

how do metal ions produce color

Answer 7

become excieted and emit light of a specific wavelength

Question 8

test for detecting the presence of starch

Answer 8

iodine test

Question 9

Qualitative or Quantitative:
- Determining the concentration of a compound in solution

Answer 9

Quantitative

Question 10

Qualitative or Quantitative:
- Identifying the cationic groups in a compound

Answer 10

Qualitative

Question 11

Qualitative or Quantitative:
- Identifying the anionic groups in a compound

Answer 11

Qualitative

Question 12

Qualitative or Quantitative:
- Identifying the functional group in a molecule

Answer 12

Qualitative

Question 13

Qualitative or Quantitative:
- Determining the elemental composition of a molecule

Answer 13

Qualitative

Question 14

chemical substance that is the subject of a chemical analysis

Answer 14

analyte

Question 15

Two measurements in quantitative analysis

Answer 15

1. mass or volume
2. measurement of some quantity that is proportional to amount of analyte

Question 16

• determine the mass of the analyte or some compound chemically related to its
• based on the principle of precipitation or volatilization methods

Answer 16

Gravimetric methods

Question 17

• determine the volume of a solution containing sufficient reagent to react completely with the analyte
• involves the measurement of the volume of a solution of known concentration, referred to as the titrant, required to react completely with a particular substance, or analyte, in the solution being analyzed

Answer 17

Volumetric methods

Question 18

substance (as a reagent solution of precisely known concentration) that is added in titration.

Answer 18

titrant

Question 19

involve the measurement of such electrical properties as voltage, current, resistance, and quantity of electrical charge

Answer 19

Electroanalytical methods

Question 20

based on the measurement of the interaction between electromagnetic radiation and analyte atoms or molecules or on the production of such radiation by analytes

Answer 20

Spectroscopic methods

Question 21

Steps in picking a method for analytical chemistry

Answer 21

1. level of accuracy
2. economic factors
3. complexity of the sample

Question 22

involves obtaining a small mass of a material whose composition accurately represents the bulk of the material being sampled

Answer 22

sampling

Question 23

sampling is frequently the most __ __ in an analysis and the source of __ __

Answer 23

• difficult step
• greatest error

Question 24

constituent parts of a material can be distinguished visually or with the aid of a microscope

Answer 24

heterogenous

Question 25

process of determining how much of a given sample is the material indicated by its name

Answer 25

assay

Question 26

under __ circumstances, no sample processing is required prior to the measurement step

Answer 26

certain

Question 27

under __ circumstances, we must process the sample in any of a variety of different ways

Answer 27

most

Question 28

Preparing Laboratory Sample (solid)

Answer 28

1. ground and mixed to ensure homogeneity 2. dried 3. moisture content may be determined

Question 29

Preparing Laboratory Sample (liquid)

Answer 29

1. liquid samples are subject to solvent evaporation

Question 30

Preparing Laboratory Sample (gas)

Answer 30

1. Gas sample dissolved in liquid 2. Must be kept inside a second container to prevent contamination of atmospheric gases

Question 31

portions of a material of approximately the same size that are carried through an analytical procedure at the same time and in the same way

Answer 31

replicates

Question 32

Replication improves and provides what?

Answer 32

1. quality of results 2. measure of reliability

Question 33

Preparing Solutions

Answer 33

1. solvent should dissolve entire sample, rapidly and completely 2. sample may require heating

Question 34

species other than the analyte that affect the final measurement

Answer 34

- interferences or - interferents

Question 35

what do interference do

Answer 35

enhance or attenuate the quantity being measured

Question 36

techniques or reactions that work for only one analyte

Answer 36

specific

Question 37

techniques or reactions that apply for only a few analytes

Answer 37

selective

Question 38

all of the components in the sample containing an analyte

Answer 38

- matrix or - sample matrix

Question 39

Ideally, the measurement of the property X is directly proportional to the concentration (CA)

Answer 39

Calibration and Measurement

Question 40

CA formula

Answer 40

CA = kX

Question 41

computing analyte concentrations are based on the raw experimental data collected in the measurement step, the chracteristics of the measurement instruments, and the stoichiometry of the analytical reaction

Answer 41

calculating results

Question 42

analytical results are incomplete without an estimate of their __

Answer 42

reliability

Question 43

used to determine if the standard deviation of a set of data is small or large when compared to the mean

Answer 43

Relative standard deviation (RSD)

Question 44

Relative standard deviation (RSD) may also be referred to as.. ?

Answer 44

Coefficient of Variation (CV)

Question 45

relative standard deviation can tell you how __ the average of your results is

Answer 45

precise