CHEM PART 1

1. Chapter One
Matter and Life
Chem100: General & Consumer
Chemistry
Natural Sciences Department
College of Science & Information Technology

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1.1 Chemistry: The Central Science
Chemistry is often referred to as “The Central Science”
because it is crucial to all other sciences.
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3. The Study of Change
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4. Present Definition
It is the study of matter – its composition,
structure, properties, the changes its undergoes
and the energy that accompanies the changes.
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u Matter: Anything that has mass and occupies
space – things you can see, touch, taste, or smell.
u Property: a characteristic that can be used to
describe a substance. Size, color, temperature are
most familiar properties of matter. Less
familiar properties include:
Chemical composition: what matter is made of.
Chemical Reactivity: how matter behaves.
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u Physical Change: Does not alter the chemical
makeup of a substance. Change is reversible.
Melting of solid ice is a physical change. In this
case only change in form takes place and the
change is reversible.
u Chemical Change: Alters chemical makeup of
a substance. Change is irreversible. Rusting of iron
is a chemical change. Here, iron combines with
oxygen and produces a new substance rust.
u Nuclear Change: Yields new element(s) not
present before the reaction.
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7. 4Fe(s) + 3O2(g) ⎯→ 2Fe2O3 (s)
2H(g) + 2H (g) ⎯→ 4He↑
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1.2 States of Matter
Matter exist in three forms: solid, liquid, and gas.
Solid: A substance that has a definite shape and
volume.
Liquid: A substance that has a definite volume but
that changes shape to fill the container.
Gas: A substance that has neither a definite volume
nor a definite shape.
Many substances, such as water, can exist in all
three states depending on the temperature. The
conversion of a substance from one state into
another is known as change of state.
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The three states - the solid state, the liquid state, and the
gaseous state - of water are shown in Figure 1.3 below.
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1.3 Classification of Matter
u Pure Substance: Uniform in its chemical
composition and properties. Sugar and water are
pure substances.
u Mixture: Composition and properties may
vary. Different amounts of sugar dissolved in
water will determine sweetness of water. Sugar
water is an example of a mixture.
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u Chemical Compounds: Substance that can
be broken down into simpler substances.
Water is a chemical compound since it can be
broken down into hydrogen and oxygen by
passing electric current through it.
u Element: Substance that can not be broken
down chemically into simpler substances.
Hydrogen, oxygen, nitrogen are example of
elements.
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The classification of matter is summarized in Fig 1.4
below.
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1.4 An Example of a Chemical
Reaction
When the element nickel, a solid metal, is
mixed with a colorless solution of
hydrochloric acid in a test tube, the nickel
is slowly eaten away, the colorless
solution turns green, and a colorless gas
bubbles out of the test tube.
Ni(s) + HCl(aq) ⎯→ NiCl2(aq) + H2↑
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1.5 Chemical Elements and Symbols
115 Elements are known until today. Only 90 of
these elements occur naturally, remaining are
produced artificially by chemists and physicist.
u Some familiar elements are iron, tin,
carbon, oxygen, hydrogen, sulfur, etc.
u Some unfamiliar elements are niobium,
rhodium, thulium, californium etc.
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Each element has its own unique symbol.
– One or two letter symbols are used to
represent elements.
– First letter is always capitalized and the
second letter is always a lower case.
– Some symbols came from elements modern
name such as ‘H’ for hydrogen, ‘O’ for
oxygen, ‘N’ for nitrogen, etc.
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u A few symbols for elements are derived
from their Latin names. For example,
‘Na’ for sodium came from its Latin name
Natrium.
u All naturally occurring elements are not
equally abundant. Oxygen and silicon
together constitute 75% of the earth’s
crust.
u Chemical Formula: A notation for
chemical compound using element
symbols and subscripts to show how many
atoms of each element are present.
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The formula for water is H2O. H2O indicates
that two hydrogen and one oxygen combined
together to produce water. When no subscript
is given for an element a subscript of ‘1’ is
understood.
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1.6 Elements and the Periodic Table
Periodic Table, shown below, is a representation of
113 elements in a tabular format.
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Large amounts of information regarding the
properties of elements is embedded in periodic
table. Elements are roughly divided into 3 groups
q Metals
q Nonmetals
q Metalloids
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Metals, nonmetals, and metalloids appear in
distinct places on the periodic table
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Metals: 89 of the 115 elements are metals. They
appear on the left side of the Periodic Table.
Some common properties of metals are:
q Solid at room temperature (except mercury
which is a liquid)
q Good conductor of heat
q Good conductor of electricity
q Malleable
q Ductile
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Nonmetals: Appear on the right side of the
Periodic Table. 17 elements are nonmetals.
Nonmetals are poor conductors of heat and
electricity.
Out of these 17 nonmetal elements
– Four are gases at room temperature (H,
N, O, etc.)
– Five are solids (sulfur)
– One is a liquid (bromine).
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Metalloids: Appear between metals on the
left side and nonmetals on the right side on
the periodic table. Their properties are
between metals and nonmetals. Boron, silicon,
arsenic are examples of some of the
metalloids.
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26. A Science for the 21st Century
Health and Medicine
Breakthroughs of the Recent Century:
1. Health and Sanitation Systems
2. Surgery with Anesthesia
3. Development of Antibiotics and Vaccines
4. Gene Therapy* (still in experimental stage)
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27. A Science for the 21st Century
Energy and Environment
Fact: Fossil Fuels (Coal, Oil and Natural Gas)
are in decline (estimates: 50-100 years)
Solution: Turn to Alternative Forms of Energy
1. Solar Energy
2. Nuclear Power
3. Wind Power
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28. A Science for the 21st Century
Materials Science
Materials Developed in the Past:
1. Plastics
2. Metal Alloys
Materials Being Developed:
1. Room Temperature Superconductors
2. Fiber Optics
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29. A Science for the 21st Century
Food and Agriculture
Common Agricultural Chemicals Used:
fertilizers, pesticides, herbicides
A question of alternatives?
Common Food Additives/Preservatives:
1. In Meat Products – sodium nitrate/nitrite
2. In Beverages – High-Fructose Corn Syrup
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Chapter Summary
u Chemistry is the study of matter.
u Matter is anything that has mass and
occupies space.
u Physical change does not alter the chemical
makeup of a substance. Change is reversible.
u Chemical change alters chemical makeup of
a substance. Change is irreversible.
u Pure substances have uniform chemical
composition and properties.
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Chapter Summary Contd.
u Composition and properties of a mixture may
vary.
u Substance that can be broken down into simpler
substances is a chemical compound.
u Substance that can not be broken down chemically
into simpler substances is known as an element.
u Elements are represented by one or two letter
symbols. First letter is always capitalized and the
second letter is always a lower case.
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Chapter Summary Contd.
u Chemical Formula is a notation for chemical
compound to show how many atoms of each element
are present.
u Periodic Table is a representation of 115 elements in
a tabular format.
u Elements are roughly divided into 3 groups
– Metals
– Nonmetals
– Metalloids
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A 21st Century Science
u Health and Medicine
u Energy and Environment
u Materials Science
u Food and Agriculture
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End of Chapter 1 Part I
Chapter One