principles of chemistry-l1.pdf

8/14/2019 Principles of chemistry-L1.pdf

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Instructor: H Rehman

Principles of Chemistry

(CHEM 101)

Sept 7, 2011


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2. Course contents

Chemical Kinetics

Basicconceptsof matter

Will reaction happen?

How Fast willreaction happen?

Atomic StructureElectrons in Atoms (QuantumMechanical View of Atom)Trends in Periodic Table

Electrons in Molecules (Bonding)

Thermodynamics andChemical Equilibrium

Acid-Base Equilibria


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3. Atomic structure

I. AtomII. Discovery of electronIII. Failure of classical mechanicsIV. Introduction to quantum mechanics


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Aristotles Continuum Theory of Matter:400BC

There is no limit to which substance can be broken down

Aristotles Theory of Matter

All matter is made of four basiccomponents (elements);

1. Earth2. Air3. Water4. Fire

Aristotle


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Democritus Atomic Theory (400 BC)

If you keep on breaking a substance into smallerand smaller units, a limit will reach beyond whichthat unit wont be further divisible. This unit whichis not further divisible is called atom.

Latin: a = not tomos = divisible


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Becher/Stahl Theory of Phlogiston

Every combustable substance contains a universal

component of fire called Phlogiston which is releasedwhen heated

Wood + fire = Ash + Phlogiston

Metal clax + fire = metal +Phlogiston

Heavy light


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Joseph Priestley:1774

Different substances react differently in dephlogisticatedand un-dephlogisticated air

un-dephlogisticated air dephlogisticated air regenerated air


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a

Antoine Lavoisier:1789

Law of conservation of mass

J.L. Proust:1799

Law of definite proportion


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Gay-Lussac: Law of combining Volumes of Gasses

The ratio between the volumes of the reactant gases andthe products can be expressed in simple whole numbers.

3H2 + N2 2NH3


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Avogadro:

At constant T and P all gasses contain equal number ofatoms or molecules

3H2 + N2 2NH3


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Daltons Atomic Theory:

Postulates of DAT

1. All matter is composed of atoms

2. Atoms of same elements are identical

3. Atoms of different elements react in definite proportions

4. Atoms can not be created or destroyed


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A theory based on Newtons Law (F = ma) usedto describe the behavior of macroscopic objects.

Given exact knowledge of the present state ofthe classical-mechanical system, we cancalculate its future state.

Laplace deterministic theory:

Classical Mechanics:

I. Atom

II. Discovery of electron

III. Failure of classical mechanicsIV. Introduction to quantum mechanics


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Complete understanding of the universe-1890s

All future truths in physical science need

to be looked for in the 6th

decimal point

Albert A. Michelson on July 2, 1984 said:

principles of chemistry-l1.pdf

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