Principles of Chemistry

Introduction to the Principles of Chemistry

Rena AbbasovaBaku Higher Oil School, September 2013

Text book:Chemistry, 2nd Editionby Blackman, Bottle, Schmid, Mocerino and Wille

Reference to book pages on notes e.g. [T p15-20]

Modes of Learning

Lectures

Tutorials

Webtests

Workshops

Private study

Lectures

New concepts , new facts

Make your own notes - Focus on the main points!

Review your notes asap after each lectures

Your attendance is obligatory!

Tutorials

Individual attention to the students

More interactive and specific than a book or a

lecture

Help develop your understanding of the subject,

not test it

Your attendance is required!

Webtests

Relate to the lecture material

Available via the University virtual learning environment – VISION

Formative not summative (This semester ONLY)

Possibility of repeated attempts (as often as you wish)

Workshops

they help develop your understanding of the

subject, not test it!

Problems will be given out in advance

Self study before workshop is obligatory!

Your attendance is required!

Private study (Self-study)

You must supplement your timetabled time

with private study!

Revising and Supplementing lectures notes

Reading the textbook

Researching and answering tutorial questions

To succeed in exam

you need to be strongly motivated:

Read the textbook

Attend lectures, tutorials and workshops and be

active

Research and answer tutorial questions

Work before and at the workshops

Use webtests

Spare no effort to private study

Schedule of course

Week Lecture Tutorial Webtest Wokshop Private study

1 Intro, 1-3 2 ≥ 6 hrs

2 4-6 2 1 (L1-4) ≥ 6 hrs

3 7-10 2 ≥ 6 hrs

4 11-13 2 2 (L6-9) 1 (L6-9) ≥ 6 hrs

5 14-16 2 3 (L10-13) 2(L10-13) ≥ 6 hrs

6 17-19 2 4 (L14-17) 3(L14-17) ≥ 6 hrs

7 20-22 2 5 (L18-21) 4(L18-21) ≥ 6 hrs

8 23-26 2 ≥ 6 hrs

9 27-29 2 6 (L22-25) 5 (L22-25) ≥ 6 hrs

10 30-32 2 7 (L26-29) 6 (L26-29) ≥ 6 hrs

11 33-35 2 8 (L30-33) 7(L30-33) ≥ 6 hrs

12 36, 37 2 9 (L34-37) 8(L34-37) ≥ 6 hrs

Principles of Chemistry

The course covers topics of General,

Inorganic and Organic Chemistry:

1. Stoichiometry and Reactions

2. Atomic Structure

3. Molecular Shape and Chemical Bonding

4. Main-Group Chemistry

5. Introductory Organic Chemistry

What is chemistry?

the study of matter and energy and the interactions between them.

It tends to focus on the properties of substances and the interactions between different types of matter, particularly reactions that involve electrons.

the study of substances and their

transformation

The building block of matter

Atom

Chemical ElementsEach elements is made of the same kind of atoms

Currently, there are about 118 elements discovered; some are found in nature and some are man-made.

Elements carry the names and symbols.

Periodic Table [Textbook p13-15]

Electronic configuration of atom

Chemistry is mostly the study of electron interactions between atoms and molecules.

Understanding the behavior of the electrons in an atom is an important part of understanding chemical reactions.

The properties of an atom's electron configuration are described by four quantum numbers: n, l, m, and s.

Orbitals that have the same principal quantum number, n, are part of the same electron shell.

Orbitals that have the same n and l, they are in the same subshell.

Principal quantum number n. n is an integer (n = 1, 2, 3, 4,etc…), n defines the size and the energy of the orbital (an electron shell).

Azimutal quantum number l, can be any number between 0 and (n-1). (l = 0, 1, 2, …,(n-1)), l defines the shape of the orbital (electron sub-shells).

Magnetic quantum number ml. can be any number between –l and +l. (m = -l, -(l-1), …0, …, (l-1), l. ml defines the orientation of the orbital.

Spin quantum number ms can be + ½ or -½. ms describes the electron spin. Electrons also have the further property of spin that can occur in two ways. Notation: ms = +½ is noted ↑; ms = -½ is noted ↓.

Quantum numbers

The Building-Up Principle

THE PERIODICITY OF ATOMIC PROPERTIES

Potential energy curves - Morse curves

When H – H distance = 74 pm,

Repulsion = Attraction

strongest bond

optimal overlap

lowest energy

CHEMICAL BOND

Intramplecular Intermolecular

The type of bond depends on the difference in electronegativity and distribution of electron density

CHEMICAL BOND

Bond type Covalent Ionic Metallic

Types of atoms involved

Mainly non-metals Some non-metals and some metals

Metals only

Nature of bonds between atoms

Sharing of electrons Transfer of electrons

Delocalisation of electrons

THEORIES OF CHEMICAL BONDING

 

 Valence bond theory: It explained the formation of covalent bonds between atoms, which is

supposed to be formed due to overlapping of atomic orbitals.

Molecular orbital theory:  The atomic orbitals of bonding atoms combine with each other by giving

rise to molecular orbitals. MO-LCAO

Molecular Shape

Valence Shell Electron Pair Repulsion TheoryVSEPR

A model in chemistry used to predict the shape of individual molecules based upon the extent of electron-pair electrostatic repulsion. It is also named Gillespie-Nyholm  theory after its two main developers.

The geometry around an atom is described by the general formula: AXmEn ,

where X is a bonded atom, E is a lone pair and (m+n) is the number of objects (sometimes called the steric number, SN) around the central atom A.

AX4 Tetrahedral AX3E (Trigonal) Pyramidal

VSEPR Molecular Shapes

e-pairs Notation Name of VSEPR shape Examples2 AX2 Linear HgCl2 , ZnI2 , CS2 , CO2

3 AX3 Trigonal planar BF3 , GaI3

AX2E Non-linear (Bent) SO2 , SnCl2

4 AX4 Tetrahedral CCl4 , CH4 , BF4-

AX3E (Trigonal) Pyramidal NH3 , OH3-

AX2E2 Non-Linear (Bent) H2O , SeCl2

5 AX5 Trigonal bipyramidal PCl5 , PF5

AX4E Distorted tetrahedral (see-sawed)

TeCl4 , SF4

AX3E2 T-Shaped ClF3 , BrF3

AX2E3 Linear I3- , ICl2

-

6 AX6 Octahedral SF6 , PF6-

AX5E Square Pyramidal IF5 , BrF5

AX4E2 Square Planar ICl4- , BrF4

-

Summary of VSEPR Molecular Shapes

Law of Mass Conservation The law of mass conservation implies that atoms can neither be created nor destroyed during a chemical reaction, although they may be rearranged, and/or their state of matter may change. The direct implication of the law of mass conservation is that chemical reaction equations must be balanced.

Types of Chemical reaction in Aqueous Solution

Precipitation/dissolution

Acid/base reactions (Brǿnsted-Lowry (B-L) )

Redox reactions

Stoichiometry

Oxidation-Reduction Reactions

Oxidation-Reduction Reactions in Aqueous Solutions

REDOX reactions can be balanced in one of two ways:

HCl + MnO2 Cl2 + MnCl2 + H2O

(1) The OXIDATION-STATE METHOD|| The oxidation number method. (2) The HALF-EQUATION METHOD || The half reaction method. (ion-electron method)

MnO2 + 4 H+ +2 е- Mn2+ + 2H2O 2 12 Cl- -2 е- Cl2 2 1________________________________________ equationMnO2 + 4 H+ +2 Cl- +2 е- Mn2+ + H2O+ Cl2 +2 е-

 

4 HCl + MnO2 = Cl2 + MnCl2 + 2 H2O

Chemistry of the Elements of the Main Group

Environmental Impact of Main Group Compounds

ACID RAIN

OZONE DEPLETION

GREENHOUSE EFFECT

What is acid rain?Acid rain typically has a pH from 4.0 to 5.4

What are the causes of acid rain? SO2 , SO3, Nox

What are the effects of acid rain?

Damages buildings, statuesCorrodes marble and metalsCauses human respiratory diseasesIncreases the acidity of soilInduces the release of aluminum ions from soil particlesAcidifies lakes

What can we do to solve the problems brought by acid rain?

OZONE DEPLETION

Ozone layer in the stratosphere protects the Earth’s surface from UV light

Ozone depletion refers to a lowered concentration of ozone in the upper atmosphere

“Holes” are formed More UV radiation is reaching the Earth’s surface

What are the causes of ozone depletion?

Presence of chlorofluorocarbons (CFCs)Presence of oxides of nitrogenPresence of halogens Presence of bromine

The 3 major greenhouse gases are: water vapour (36 to 70%), carbon dioxide (9 to 26%), methane (4 to 9%). Other contributors include nitrous oxide, ozone and CFCs.

Most of the incoming solar radiation is in the visible part of the spectrumMost visible light passes through the atmosphere without being absorbedThe earth radiates heat back out towards space when warmed upMuch of the radiation does not escape into spaceMost is trapped by certain gases in the atmosphere, carbon dioxide and particular water vapour

GREENHOUSE EFFECTGreenhouse effect is an excess of heat created due to the high concentrations of some gases

What is global warming?

Global warming refers to the gradual increase in the average temperature in the atmosphere

Increase in concentration of greenhouse gases in the atmosphere

The heat loss from the Earth to the Space is slowed down

An enhancement of the greenhouse effect leads to global warming

Greenhouse gases include carbon dioxide, chlorofluorocarbons, methane, nitrous oxides, ozone, water vapour, etc

Thank you for attention!