chem1101a lect 1

8/3/2019 Chem1101A Lect 1

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INTRODUCTORY CHEMISTRY

CHEM 1101A

Lecturer: Dr. Duanne Biggs

Email: [email protected]

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8/3/2019 Chem1101A Lect 1


Outline

States of matter

Kinetic particle Theory

Element, compounds and mixtures

Solutions, suspensions and colliods

Methods of separation

Gas Laws: Boyle’s Law, Charles Law,Gay-Lussac Law

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STATES OF MATTER

• The Four States of Matter

• Four States

• Solid

• Liquid

• Gas• Plasma (General Knowledge)

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STATES OF MATTER

Based upon particle arrangement

Based upon energy of particles

Based upon distance between particles

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Kinetic Particle Theory

• KPT is just the view that everything is made of

tiny particles that are in motion, hence theterm “kinetic”. This topic is concerned with

exhibited by these particles.

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Characteristics of the 3 states

• Solid: Particles are closely packed in an orderly

arrangement, and vibrate in fixed positions.

• L qu : Partic es are oose y arrange ut sticlose together, and move randomly.

• Gas: Particles are far apart, with no

arrangement, and move randomly.

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States of Matter

SolidsParticles of solids are tightly

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,

position.

Solids have a definite shape and adefinite volume.

Solids have an infinite number of free surfaces.

8/3/2019 Chem1101A Lect 1


States of Matter

LiquidsParticles of liquids are tightly

packed, but are far enough apart

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to slide over one another.

Liquids have an indefinite shape

and a definite volume.

Liquids have one free surface.

8/3/2019 Chem1101A Lect 1


States of Matter

GasesParticles of gases are very far apart and move

freely.

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Gases have an indefinite shape and an

indefinite volume.

Gases have no free surfaces.

8/3/2019 Chem1101A Lect 1


States of Matter

Plasma

A plasma is an ionized gas.

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A plasma is a very good conductor of electricity and is affected by magnetic fields.

Plasma, like gases have an indefinite shapeand an indefinite volume.

8/3/2019 Chem1101A Lect 1


States of Matter

Sublimation is the conversion of a solid directly to

a gas without passing through the liquid state;the reverse of that process is called deposition.

Water is a substance that is familiar to us in allthree physical states. The molecules are closetogether in the solid and the liquid but far apart

in the gas. The molecules in the solid arerelatively fixed in position, but those in the liquidand gas can flow around each other.

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States of Matter

The changes shown in blue are endothermic (absorb

heat); those shown in red are exothermic (release heat).12

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STATES OF MATTER

SOLID LIQUID GAS PLASMA

Tightly packed, in a

regular pattern

Vibrate, but do not

move from place to

place

Close together with

no regular

arrangement.

Vibrate, move

about, and slide

past each other

Well separated with

no regular

arrangement.

Vibrate and move

freely at high

speeds

Has no definite

volume or shape

and is composed of

electrical charged

particles

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Energy

• Changes from one state to another involve the

gain or loss of energy. Energy is absorbed togive particles more energy, while energy is lost

.

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Compounds and Mixtures

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Elements and Chemical

Compounds

Elements are pure substances that contain

only one kind of atom.

Chemical compound is a pure substance that

different elements combine and create a new

material with properties completely unlike

those of its constituent elements.

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Mixtures

• Mixtures are simply blends of two or more

substances added together in some randomproportion without chemically changing the

• Heterogeneous

• Homogeneous

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Heterogeneous mixtures

Heterogeneous mixtures are those in which the

mixing is not uniform and which thereforehave regions of different composition.

• Components are distinguishable

Examples: fruit salad, vegetable soup, etc.

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Homogeneous mixtures

• Homogeneous mixtures are those in which

the mixing is uniform and which thereforehave a constant composition throughout.

• Components are indistinguishable

• May or may not scatter light

Examples: milk, yogurt, etc.

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Matter

Arrows indicate the general means by which matter can beseparated

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Separation

A mixture of iron and sulfur is a heterogeneous mixture.

Like any mixture, it can be separated by physical means,

such as removing the iron with a magnet. 21

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Solution

A solution is a homogeneous mixture of two or

more components. The dissolving agent is thesolvent. The substance which is dissolved is the

.

Example: Sugar and water

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Suspensions

• The particles in suspensions are larger than

those found in solutions. Components of asuspension can be evenly distributed by a

,

contents, but the components will settle out.

• Example: Oil and Water

»Sand in water

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Colloids

• Particles intermediate in size between those

found in solutions and suspensions can bemixed such that they remain evenly

.

• Eg: Smoke – air is called the continuous phase

- the particles are called the

disperse phase• Example: starch in water

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GAS LAWS

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GAS LAWS• Unlike solids and liquids, different gases show

remarkably similar physical behavior

regardless of their chemical makeup. Gasesare considered fluids.

“

flow.”

• Gases Have Low Density

• Gases Are Highly Compressible• Gases Completely Fill a Container

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GAS LAWS

• Physical properties of any gas can be defined

by four variables: pressure (P)

temperature (T),

vo ume V ,number of moles (n).

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GAS LAWS

Boyle’s Law:

for a fixed amount of gas (n) at a constant

temperature (T), the volume of the gas

and the volume of the gas decreases as the

pressure of the gas increases

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GAS LAWS

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GAS LAW

• Charles’ Law: The Relationship Between

Volume and Temperature

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GAS LAWS

• Charles’ Law:

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GAS LAWS• Gay-Lussac’s law: the law that states that the

pressure of a gas at a constant volume is directlyproportional to the absolute temperature.

Pressure of a as is ro ortional to its absolute

temperature, the following equation is true for asample of constant volume.

P = kT

This equation can be rearranged to the followingform.

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GAS LAWS

Gay-Lussac’s Law

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chem1101a lect 1

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