Chapter 1
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Science comes from the Latin word scire,
which means, “to know.”
We study science in order to understand the
world around us.
Chemistry is often called the central science
as so many naturally occurring phenomena
involve chemical change.
Pure Science vs.
Pure Science is the search for a
better understanding of our
world.
Applied
Applied science studies the
application of scientific discoveries.
An applied scientist wants to know
A pure scientist searches for new
how he/she can use that
information.
information.
Chemist
Chemical Engineer
3 Branches of Science
Life science
Earth science
Physical Science
deals with living
things, their
parts, and
actions.
study of the
Earth.
study of matter
and energy
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1.
2.
3.
4.
5.
6.
Analytical chemistry
Organic chemistry
Inorganic chemistry
Physical chemistry
Biochemistry
Nuclear chemistry
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In a recent survey by American Chemical Society,
entering college students were asked to express
their attitudes about science courses.
Chemistry was rated as the most relevant science
course.
64% rated chemistry as highly relevant to their
daily lives.
Unfortunately, 83% thought chemistry was a
difficult subject.
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The earliest concept of science began with the
ancient Chinese, Egyptian, and Greek
civilizations.
The Chinese believed the universe was created by
the interaction between two forces, Yin and Yang,
and were responsible for everything in nature.
600 B.C. The Greeks
◦ Science was pure reasoning.
◦ The universe consisted of a single element.
◦ Thales, founder of Greek science, thought that water
was the single element.
 Earth is a flat disc floating on a universe of water.
 Air and Space were less dense forms of water and the
Earth more dense.
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350 B.C. Aristotle, Greek
◦ Air, earth, water, and fire were basic elements.
◦ Aristotle’s influence was so great that this theory
dominated our understanding for nearly 2000
years.
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Destruction of the Greek civilization, European
science fell and did not reappear until the
Middle Ages.
Eighth century A.D., Arabs
◦ Introduce the pseudoscience of alchemy.
◦ Alchemists looked for the magical elixir that had
miraculous healing powers and could transmute
base metals into gold.
◦ Led to planned, systematic, scientific procedures
and laboratory apparatus.
◦ Mainly worked by trial and error.
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Take all the mineral salts there are, also all salts
of animal and vegetable origin. Add all the
metals and minerals, omitting none. Take two
parts of the salts and grate in one part of the
metals and minerals. Melt this in a crucible,
forming a mass that reflects the essence of the
world in all its colors. Pulverize this and pour
vinegar over it. Pour off the red liquid into
English wine bottles, filling them half-full. Seal
them with the bladder of an ox (not that of a
pig). Punch a hole in the top with a coarse
needle. Put the bottles in hot sand for three
months. Vapor will escape through the hole in
the top, leaving a red powder…
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During the 1200’s, Robert Bacon, English
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1661 Robert Boyle, English
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Late 1700’s Antoine Lavoisier, French
◦ Gain an understanding of the natural world through
observations and experimentation rather than pure
logic.
◦ Published The Sceptical Chymist
◦ Stated that scientific speculation was worthless unless
it was supported by experimental evidence.
◦ Led to the scientific method.
◦ Organized chemistry into a comprehensible science.
◦ Transformed chemistry from a science of observation
to the science of measurement that it is today.
◦ Organized a magnificent laboratory where scientists
like Benjamin Franklin and Thomas Jefferson visited.
◦ Considered to be the founder of modern chemistry.
 systematic approach to problem solving.
 differs depending on what you are studying but there
are a few basic steps.
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2.
3.
4.
5.
6.
7.
State the problem.
Gather information on the problem.
Form a hypothesis.
Perform experiments to test the hypothesis.
Record and analyze data.
State a conclusion.
Repeat the work.
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STATE THE PROBLEM:
◦ What are you trying to find out?
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GATHER INFORMATION ON THE
PROBLEM:
◦ Collect observations.
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FORM A HYPOTHESIS:
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PERFORM EXPERIMENTS TO TEST THE
HYPOTHESIS:
◦ Proposed solution, a tentative explanation
◦ Educated guess,
◦ Carefully devised plans and procedures.
In experiments there are factors that remain the same and there are factors
that change…
The constant and the variable…….
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Constant(s) remain unchanged throughout the experiment.
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The variable is the factor being tested. It changes or varies
during an experiment.
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There are two types of variables:
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the dependent and the independent.
The independent variable is the variable that the
experimenter physically changes.
◦ (Only change one at a time!!!!)
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The dependent variable changes because the independent
variable changed. It DEPENDS on the independent variable.
The control is the dependent variable, not influenced by the
independent variable. Conducting the experiment without
the independent variable, gives you a starting point for an
experiment, and shows the need for the independent
variable.
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RECORDING AND ANALYZING DATA:
◦ Record observations and measurements (aka DATA)
◦ Usually written in a table.
◦ A Visual representation of the data is called a
GRAPH.
 The x-axis (horizontal axis, left-to-right axis)
represents the independent variable.
 The y-axis (vertical axis, up-and-down axis)
represents the dependent variable.
Vertical axis
Horizontal Axis
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STATE A CONCLUSION:
◦ Is there a pattern? Can you make a theory?
 A theory gives a universally accepted explanation of the
problem. Of course theories should be constantly challenged
and may be refined as and when new data comes to light.
 Theories are different to laws. A law is a summary of
observed (measurable) behavior, whereas a theory is an
explanation of behavior. A law tells what happens; a theory
(model) is our attempt to explain why it happens. Laws state
what general behavior is observed to occur naturally.
 For example, the law of conservation of mass exists since it
has been consistently observed that during all chemical
changes the overall mass of the substances involved remains
unchanged.
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REPEAT THE WORK:
◦ Check to see if the data is correct.