Chapter 7: Introduction to Ana Chem

Question 1

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

Answer 1

Analytical Chemistry

Question 2

Application of Analytical chemistry

Answer 2

applied throughout industry, medicine, and all the sciences

Question 3

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

Answer 3

Qualitative analysis

Question 4

indicates the amount of each substance in a sample.

Answer 4

Quantitative analysis

Question 5

Qualitative or quantitative : Test for protein

Answer 5

Qualitative

Question 6

Qualitative or quantitative : Iodine test for starch, color of the solution indicates the presence of starch

Answer 6

Qualitative

Question 7

Qualitative or quantitative : Iodine test for starch, measuring the light that passes through a sample.

Answer 7

Quantitative

Question 8

a chemical substance that is the subject of a chemical analysis

Answer 8

Analyte

Question 9

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

Answer 9

1. Mass or the volume of the sample to be analyzed.
2. the measurement of some quantity that is proportional to the amount of analyte.

Question 10

Quantitative analytical methods (classification)

Answer 10

1. Gravimetric Methods
2. Volumetric methods
3. Eletroanalytical methods
4. Spectroscopic methods

Question 11

determine the mass of the analyte or some
compound chemically related to it.

Answer 11

Gravimetric methods

Question 12

Gravimetric methods is based on the principle of?

Answer 12

• Precipitation or volatilization methods

Question 13

steps in Gravimetric method

Answer 13

a. Weighing the sample to be analyze
b. Dissolving this sample in water
c. Adding suitable chemical to form a precipitate.
d. Filtering to collect the precipitate
e. Repeated drying and weighing (until a constant mass of precipitate is obtained)

Question 14

determine the volume of a solution containing sufficient reagent to react completely with the analyte.

Answer 14

Volumetric methods

Question 15

measurement of the volume of a solution of known concentration

Answer 15

Titrant

Question 16

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

Answer 16

Eletroanalytical methods

Question 17

Electrical properties used to measure

Answer 17

• voltage
• current
• resistance
• quantity of electrical charge

Question 18

are based on measurement of the interaction between electromagnetic radiation and analyte atoms or molecules

Answer 18

Spectroscopic methods

Question 19

Electro magnetic spectrum from lowest to highest

Answer 19

• Radio
• Microwave
• Infrared
• Visible
• Ultraviolet
• X-ray
• Gamma Ray

Question 20

10^3

Answer 20

Radiowave

Question 21

10^-2

Answer 21

Microwave

Question 22

10^-5

Answer 22

Infrared

Question 23

10^-6

Answer 23

Visible

Question 24

10^-8

Answer 24

Ultraviolet

Question 25

10^-10

Answer 25

X-Ray

Question 26

10^-12

Answer 26

Gamma Ray

Question 27

General Steps in Quantiative analysis

Answer 27

1. Select Method 2. Acquire sample 3. Process sample

Question 28

Picking a method steps

Answer 28

1. Consider in the selection process is the level of accuracy required. 2. Second consideration to economic factors is the number of samples to be analyze 3. The complexity of the sample and the number of components in the sample.

Question 29

Acquiring the sample steps

Answer 29

Sampling, obtaining a small mass of materal whose composition represents tha bulk

Question 30

involves obtaining a small mass of a material

Answer 30

Sampling

Question 31

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

Answer 31

A material is heterogeneous

Question 32

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

Answer 32

Assay

Question 33

Processing the sample

Answer 33

- Preparation of a laboratory sample. - Defining replicate samples - Preparing solutions

Question 34

Steps of preparing a laboratory sample: Solid

Answer 34

- Ground to decrease particle size, mixed to ensure homogeneity, and stored for various lengths of time before analysis - To Dry the samples before starting analysis (due to loss or gain of water changes in solid)

Question 35

are subject to solvent evaporation.

Answer 35

Liquid Samples

Question 36

are 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 36

Replicates or replicate sample

Question 37

Replicate samples analytical procedure are .....

Answer 37

carried at the same time and in the same way

Question 38

improves the quality of the results and provides a measure of their reliability.

Answer 38

Replication

Question 39

are performed on the results to establish their reliability

Answer 39

Statistical tests

Question 40

Steps in preparing solutions

Answer 40

1. Solvent should dissolve the entire samle 2. The sample may require heating with aqueous solutions. 3. It may be necessary to ignight the sample in or oxygen or perfrom high-temp fusion.

Question 41

Species other than the analyte that affect the final measurement

Answer 41

Interferences or interferents

Question 42

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

Answer 42

Specific

Question 43

Techniques or reactions that apply for only a few analytes are

Answer 43

selective

Question 44

is all of the components in the sample containing an analyte

Answer 44

Matrix or sample matrix

Question 45

General steps in quantitative analysis

Answer 45

1. Select method 2. Acquire sample 3. Process sample