Chapter 8 - Introduction to Analytical Chemistry

Question 1

It is the science of obtaining, processing, and communicating information about the composition and structure of matter

Answer 1

Analytical Chemistry

Question 2

Analyrtical Chemistry is the ____ and ____ of determining what _____ __ and how much of it _____

Answer 2

• art and science
• matter is
• exists

Question 3

Analytical chemistry is a ______ ____ consisting of a set of ____ ____ and _____ that are useful in all fields of _____ and ______

Answer 3

• measurement science
• powerful ideas and methods
• science and engineering

Question 4

Both _____ and _____ information are required in an analysis

Answer 4

Qualitative and Quantitative

Question 5

The role of analytic chemistry

Answer 5

is applied throughout industry, medicine, and all the science

Question 6

The role of quatitative analytical measurements

Answer 6

play a vital role in chemistry, biochemistry, biology, geology, physics, and the other sciences

Question 7

The _______ _____ of chemical analysis makes it a vital tool in medical, industrial, government, and academic laboratories throughout the world

Answer 7

interdisciplinary nature

Question 8

It reveals the identity of the elements and compounds in a sample

Answer 8

Qualitative analysis

Question 9

Qualitative analysis reveals the ______ of the elements and compounds in a sample

Answer 9

identity

Question 10

It indicates the amount of each substance in a sample

Answer 10

Quantitative analysis

Question 11

Quantitative analysis indicates the _____ of each substance in a sample

Answer 11

amount

Question 12

It is based on obsevations (involves the senses)

Answer 12

Qualitative Data

Question 13

It is based on numbers (measurement or counting)

Answer 13

Quantitative Data

Question 14

Qualitative Data is based on

Answer 14

observation (involves the senses)

Question 15

Quantitative Data is based on

Answer 15

numbers (measurement or counting)

Question 16

It is a chemical substance that is the subject of a chemical analysis

Answer 16

Analyte

Question 17

The results of a typical quantitative analysis are computed from two measurements:

Answer 17

1. Mass or volume (gravimetric and volumetric methods)
2. Measurement of some quantity that is proportional to the amount of analyte in the sample (electrochemical and spectrometric methods)

Question 18

Quantitative analytical methods (classification)

Answer 18

1. Gravimetric methods
2. Volumetric methods
3. Electroanalytical methods
4. Spectroscopic methods

Question 19

Gravimetric methods determine the _____ of the analyte or some compound chemically related to it

Answer 19

mass

Question 20

Gravimetric methods is basen on what principle?

Answer 20

Based on the principle of precipitation or volatilization methods

Question 21

Volumetric methods determine the ______ of a solution containing sufficient reagent to react completely with the analyte

Answer 21

volume

Question 22

What measurement is involve in Volumetric methods?

Answer 22

Measurement of the volume of a solution of known concentration, referred to as the titrant

Question 23

Electroanalytical methods involve the measurement of such ____ _____

Answer 23

electrical properties

Question 24

Measurement of electrical properties

Answer 24

• voltage
• current
• resistance
• quantity of electrical charge

Question 25

Spectroscopic methods are based on measurement of the interaction between ______ ______ and _____ ____ or molecules or on the ______ of such ______ by analytes.

Answer 25

- electromagnetic radiation - analyte atoms - production of such radiation

Question 26

General steps in a quantitative analysis

Answer 26

1. Selec method 2. Acquire sample 3. Process sample: (1) Is sample soluble? (If no, carry out chemical dissolution) and (If yes, proceed to step 5) (2) Measurable property? (If no, change chemical form) and (If yes, proceed to step 6) 4. Eliminate interferences 5. Measure proerty X (Calibration and Measurement) 6. Calculate results 7. Estimate reliability of results

Question 27

In picking a method, what is the first question to be considered?

Answer 27

The level of accuracy required

Question 28

Second consideration in picking a method

Answer 28

Related to economic factors is the number of samples to be analyzed

Question 29

It always influence the choice of method to some degree

Answer 29

Complexity of the sample and the number of components in the sample

Question 30

In acquiring a sample, ______ involves obtaining a ____ ____ of a material whose composition accurately ______ the ____ of the material being samples

Answer 30

- Sampling - small mass - represents the bulk

Question 31

Sampling is frequently the most ______ step in an analysis and the _____ of ____ ____

Answer 31

- difficult - source of greatest error

Question 32

A material is ______ if its constituent parts can be distinguished visually or with the aid of a microscope

Answer 32

heterogeneous

Question 33

How can you say if the material is heterogeneous in acquiring the sample?

Answer 33

If its constituent parts can be distinguished visually or with the aid of a miscroscope

Question 34

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

Answer 34

Assay

Question 35

Under _____ circumstances, no sample processing is required prior to the measurement step

Answer 35

certain

Question 36

Under _____ circumstances, we must process the sample in any of a variety of different ways

Answer 36

most

Question 37

First step in processing the sample

Answer 37

The preparation of a laboratory sample

Question 38

In preparing a laboratory sample, a solid sample is ____ to decrease particel size, _____ to ensure homogeneity, and stored for various lengths of time before analysis begins

Answer 38

- ground - mixed

Question 39

It is good ideas to ____ _____ just before starting analysis because any ____ or ____ of water changes the chemical composition of _____

Answer 39

- dry sample - loss or gain - solids

Question 40

What samples are subject to solvent evaporation?

Answer 40

Liquid

Question 41

Alternatively, the _____ ____ of the sample can be determined at the time of the analysis in a _____ _____ _____

Answer 41

- moisture content - separate analytical procedure

Question 42

If the analyte is a ____ dissolved in a liquid, analyte must be kept inside a _____ _____ _____ to prevent ______ by ________ _____

Answer 42

- gas - inside a second seales container - contamination - atmospheric gases

Question 43

What is required to preserve the integrity of the sample?

Answer 43

Extraordinary measures - sample manipulation - measurement in an inert atmosphere

Question 44

It is a 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 44

Replicate samples or replicates

Question 45

Replication improves the ______ of the _____ and provides a ______ of their ______

Answer 45

- quality of the results - provides a measure of their reliability

Question 46

________ measurements on replicates are usually _____, and various _____ ____ are performed on the results to _____ their _____

Answer 46

- Quantitative - averaged - statistical tests - establish their reliability

Question 47

In preparing solutions: physical and chemical changes, _____ should dissolve the entire sample, including the _____, _____ and _____

Answer 47

- solvent - analyte - rapidly and completely

Question 48

Samples that requires heating

Answer 48

Aqueous solutions of strong acids, strong bases, oxidizing agents, reducing agents, or some combination of such reagents

Question 49

It may be necessary to _____ the sample in ___ or _____ or perform a _________ _____ of the sample in the presence of various _____

Answer 49

- ignite - air or oxygen - high-temperature fusion - fluxes

Question 50

It is a species other than analyte that affect the final measurement

Answer 50

Interferences, or interferents

Question 51

An interference is a species that _____ an ____ in an analysis by ______ or _______ (making smaller) the quantity being measured

Answer 51

- causes an error - enhancing or attenuating

Question 52

Techniques or reactions that work for only one analyte are said to be ______

Answer 52

specific

Question 53

Tehniques or reactions that apply for only a few analytes are _____

Answer 53

selective

Question 54

It is called to all of the components in the sample containing an analyte

Answer 54

Matrix or Sample Matrix

Question 55

The measurement of the ______ is _____ _____ to the _____ (C sub A)

Answer 55

- property X - directly proportional - concenration

Question 56

Formula for calibration and measurement

Answer 56

CA = kX where k is a proportionality constant

Question 57

Basis of calculating the results

Answer 57

based on the raw experimental data collected in the measurement step, the characteristics of the measurement instruments, and the stoichiometry of the analytical reaction

Question 58

Analytical results are ______ without an ______ of their ______

Answer 58

- incomplete - estimate of their reliability

Question 59

It is used to determine if the standard deviation (σ) of a set of data is small or large when compared to the mean (µ)

Answer 59

Relative Standard Deviation (RSD) or Coefficient of Variation (CV)

Question 60

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

Answer 60

precise

Question 61

A ________ provides a number called ________ that is directly proportional to the _____ ______ , which is also proportional to the ______ of the ______ responsible for the _____

Answer 61

- spectrophotometer - absorbance - color intensity - concentration of the species - color