ANALYTICAL CHEMISTRY docx

Note to the class• Welcome to Chem 321, a key course to your future success in analytical data analysis and experimental design of any chemical related problems in every scientific disci

Welcome to Chem 321

A key course to your future success

ANALYTICAL CHEMISTRY

COURSE OUTLINE

Office: Alfriend Chemistry Building Room 201

Right after the class

Teaching Assistant: Dr Tao Huang and Jill Lowman

Email: xhxu@odu.edu

MW 5:45 – 7:00 PM OCNPS Room 200

Class Time & Place

¾ MATH 102 or equivalent

Pre-requisites

Quantitative Chemical Analysis, 7 th edition, D Harris, Freeman, 2007

About Textbook

¾ Preface

¾ Chapter 1-16 (Chem 321)

¾ Summary

¾ Questions and Problems

¾ Answers to the problems: in the reserved desk in the library

¾ Glossary G-1… on the back of the book

¾ Chapters heavily associated with Chem 322

• Visit this site as frequently as possible, especially before and after every class

• You will need Acrobat Reader to download large documents

Honor Code

• Students registered for CHEM 321 are

expected to obey the ODU Honor Code!!!

¾ Attendance at class meeting is compulsory

¾ Regular and punctual class attendance is

required of all students

¾ If you are absent, you will be responsible for everything covered in class including any

handouts (e.g., problem sets, answers, sample tests, etc).

Absence from Exams

¾ Missed exams may be made up only with a

medical excuse (written by physician or health center), death or hospitalization in the family

¾ Without these reasons, one will earn a “zero”

grade on that test

¾ No exceptions will be made Please contact me prior to the exam if you must be absent.

¾ Assigned homework is mandatory

¾ Working on these assignments in a timely manner is the best way to learn the material and get good grades

¾ I may check your assignments and sample your

homework on the due date even though it may not be

graded

¾ The brief answers to assigned problems are available in the solution book, which is placed in the reserved desk in the library

• 4 unit tests and a comprehensive final examination

• Average cumulated grade = unit tests

(70%) and final exam (30%)

02/12, 14,

19 8 Activities and Systematic Treatment of Equilibrium 8-A, B, C, E, F, G, 2, 4, 11, 12, 18, 20, 24, 26 02/21 9, 11 Monoprotic Acid-Base Equilibrium 9-B, D, E, 2, 5, 6, 22, 23, 27, 28, 33 02/26 6-9 Recitation and help session

02/28 2nd Unit Test (Chapter 6-9)

03/05-10 Spring Break- No classes

03/12, 14 10, 11 Polyprotic acid-Base Equilibrium 10-A, B, D, 4, 11, 17, 18, 23

03/19, 23 11 Acid-Base Titration 11-A, B, F, 3, 6, 14, 19, 23

03/26,28 12 EDTA Titration 12-C, D, 1, 2, 3, 7, 8, 24, 34

04/02 3rd Unit Test (Chapter 10-12)

04/04, 09 14 Fundamentals of Electrochemistry 14-B, C, D, 2, 10, 25

04/11,16 15 Electrodes and Potentiometry 15-4, 8, 9, 21, 26

04/18 16 Redox Titration 16-A, 1, 2, 6, 13

04/23 4th Unit Test (Chapter 14-16)

04/30 3:45-6:45 PM Comprehensive Final Examination (Chapter 1-16, except 2, 5 and 13)

Note to the class

• Welcome to Chem 321, a key course to your future success in analytical data analysis and experimental design of any chemical related problems in every scientific disciplinary including chemistry , biology ,

biotechnology , forensic science , food science , material science , medicine , environmental science , etc

• Whether you aim to be a brilliant scientist, a medical doctoral, a technician or a good cook, you will find this course essential and helpful for your future career

What are we going to do in the class ??

• We will introduce basic analytical concepts and theories and focus on data analysis and interpretation

Six tips for success in this class

• actively attending every class and take good

notes

• improving your math (good math is absolutely

essential)

• completing all homework and study textbook,

class notes and slides

• asking questions

• coming to Dr Xu’s office hours

• visiting course website frequently

Good-luck to you!!

-Dr Nancy Xu

Chapter 1: Introduction & Measurements

What is Analytical Chemistry?

“Analytical Chemistry is what analytical chemists do.”

- C N Reilley

Roles of Analytical Chemistry

¾ Play a vital roles in all sciences, just to name of a few: chemistry, biology, biotechnology, forensic science, food science, material science, medicine,

environmental science, etc

¾ Examples of achievement of Analytical chemistry:

¾ Breakthrough of the century: Sequence of Human

Genome, Analytical chemists-capillary

electrophoresis

determination of the amount of species or analytes, in

numerical terms Hence, Math is heavily involved.

9 In order to perform quantitative analysis, typically

one needs to complete qualitative analysis

9 One needs to know what it is and then select the

means to determine the amount

Classification of Quantitative

Methods of Analysis

¾ Gravimetric Method : mass is measured

¾ Volumetric Method : volume is measured or used

to determine amount of sample via concentration.

¾ Instrumental Method : use an instrumental

technique to assay the amount of sample:

¾Such as: Electroanalytical based upon electron-transfer

Spectroscopy including mass spectrometry

(***hot) (proteomic)

Steps in a Typical Quantitative Analysis

Units

SI Units

Weight & Mass

¾ Weight is the force of gravitational

attraction between that matter and the earth.

I Review of Stoichiometry - please refer to your freshman

chemistry text to review this concept.

A Empirical vs molecular or structural formulas:

ratio between the different elements composing the molecule

Example: HO, H2CO

atoms of each element found in the molecule

Example: H2O2, H4C2O2, C2H5OH, C2H4O2, C3H6O3, C6H12O6

molecule as well as the numbers of atoms of each element

Example: HOOH, (CH3)3COH, CH3CH2OCH2CH3,

B The Mole (mol) :

A unit which defines the number of units of a chemical species (molecules, atoms, ions, etc.)

and from which we can calculate the weight of the species

if we have a knowledge of the chemical formula of that species

6.022 x 1023 particles is one mole

00

2 MW

¾Solute: a minor species in a solution

¾Solvent: a major species in a solution

(e.g., water is a solvent for aqueous solution)

Chemical Concentrations

¾ Molar Concentrations:

¾ Mola r ity (M) = solute/solution (mol/L)

¾ Mola l ity (m) = solute/solvent (mol/kg)

¾ Percent Composition

¾ Weight percent

¾Parts per million (ppm)

¾Parts per billion (ppb)

¾ Volume percent

of Volume

(mole) Solute

of Moles

of

Number

(g/mol) solute

of

MW

(g) Solute

of

Weight (mole)

Solute of

Moles of

Analytical Molarity:

The total number moles of a solute (regardless its chemical state)

in one liter of solution

Example-I-3:

117.0 g of NaCl dissolved in 1.00 L of water has an analytical

concentration of _ mol /L MW of NaCl = 58.5 g/mol

Concentration

mole 00

.

2 5

58

0

117 MW

W NaCl

00

2 L

00 1

moles 00

.

2 (L)

V

Mole

C NaCl

Example I-4:

294.0 g of H 2 SO 4 dissolved in 1.00 L of water has an analytical concentration of mol/L MW of H 2 SO 4 = 98.0 g/mol

moles 00

.

3 g/mol

0 98

g 0

294 MW

W SO

H of

Mole

4 2

4 2

SO H

SO

H 4

M 00 3 mole/L

00

3 L

00 1

moles 00

.

3 (L)

Mola l ity

(kg) solvent

of Weight

(mole) Solute

of moles

of Number

Cweight =

¾ Density:

Expresses the mass of a substance per unit volume.

In SI Units: density unit - g /mL or kg/L

Example: Density of water is approximately 1.00 g/mL at 4 0 C Weight = Volume x density

Density

Practice at Home

Assume density of solution in Examples I-3 and I-4 = 1 g/ml3,

what is the molality of the solution in Examples I-3 and I-4, respectively?

x solution of

mass

solute of

mass (w/w)

percent

% 100

x solution of

volume

solute of

volume (v/v)

percent

% 100

x (mL)

solution of

volume

(g) solute

of mass

(w/v) percent

ume weight/vol

=

2) Mole of NH3 at 14.3 M in 1.00 L=14.3 (mol/L) x 1.00 L=14.3 mol

3) Weight of NH3 at14.3 M in 1.00 L = Mole of NH3 x MW of NH3

solution of

mass

solute of

mass (w/w)

percent

Example I-6:

What is the molar concentration of an aqueous ammonia (NH 3 )

solution with density = 0.900 g/mL (900 g/L) and 27.0%

solution of

mass

solute of

mass (w/w)

percent

W NH3 = CNH3VNH3 x MW of NH3 = 243 g

CNH3 = 14.3 mol/L = 14.3 M

Example I-7: What is the v/v% of ethanol in a solution prepared

by mixing 5.00 mLof ethanol with enough water to give 1.00 L of solution?

0

%

100 L

00 1

L 10

00 5

% 100

x solution of

volume

solute of

volume (v/v)

percent Volume

pph 10

x solution of

mass

solute of

mass (w/w)

ppt 10

x solution of

mass

solute of

mass (w/w)

parts per hundred (pph) & parts per thousand (ppt )

ppm 10

x solution of

mass

solute of

mass (w/w)

ppb 10

x solution

of mass

solute of

mass (w/w)

parts per million (ppm) & parts per billion (ppb)

ppt 10

x solution

of mass

solute of

mass (w/w)

parts per trillion (ppt)

Stoichiometric Calculations

II Stoichiometric Calculations:

¾stoichiometric calculations are based on the combining ratios

of reactants which result in specific products

¾They are expressed in terms of moles

¾ when you are given the mass of a reactant or product, you

should first convert the mass to moles to determine the

amount of reactant that will be consumed or product that will

be produced for a given reaction

¾If the final answer is to be given in a mass unit, then the

moles must be converted to grams

3

AgNO

9 169

106

33 2 2

.

169 0

106

33

2 2

Example I-9

1 mol

0

W

3

2 CO Ag

7 275

106

33 2 1

1

3

2 CO Ag

x

g 06

6 7

.

275 0

106

33

2 1

Preparation of Solution

¾Solute

¾Solvent

¾Total Solution

Example I-10:

To prepare a solution with 0.500 M of Cl- from BaCl2 • 2H2O How much of the BaCl2 • 2H2O must be used to prepare 1.00 liter of solution? Assume BaCl2 completely dissociates:

C

molemole

mole2

-

-2 -

2 BaCl

Cl Cl

BaCl Cl

BaCl

=

=

=

¾ Dilution

the number of moles are the same in dilute and

concentrated solutions!

Units: V: either in L and mL

C: M (mol/L) or mM (mmol/L)

Be sure to match units for both dilute and concentrated solutions

Volumetric Calculations

25

0 4

1 x 00 1

V

xV (M)

C (M)

C

dilute HCl,

ed concentrat HCl,

ed concentrat

HCl, dilute

Any Questions???

The End!