Chapter 1
Introduction to Chemistry
Section 1.1
The Stories of Two
Chemicals
What is ozone?
O3
Ultraviolet
radiation
Oxygen
O2
Formation
How does it protect us?
Destruction absorbs UV radiation
Where is Ozone?
What was happening to the ozone
layer?
1979
2000
2003
What is a chlorofluorocarbon
(CFC)?
Carbon compound containing chlorine and fluorine
What are CFC’s used for?
• Refrigerators and
freezers
• Plastic foams
• Propellants for spray
cans
It’s here that
the tale of
these two
chemicals
comes
together!
What do CFC’s do to ozone?
1.2 Chemistry and Matter
•
What is it?
–
•
Study of the composition of matter and its changes.
Branches.
–
–
–
–
–
Organic chemistry – carbon chemistry.
Inorganic chemistry – noncarbon chemistry.
Physical chemistry – behavior of chemicals.
Analytical chemistry – composition.
Biochemistry – chemistry of living organisms.
1.2 Chemistry and Matter
• Matter – has mass and takes up space.
– Mass – amount of matter an object contains.
– Weight – pull of gravity on an object (proportional
to mass and force of gravity).
– Volume – amount of space an object takes up.
– Inertia – resistance to a change in motion
(proportional to mass).
1.3 Scientific Method
1.3 Scientific Method
•
Scientific Method
–
Systematic approach used to understand
the world around us.
Observation
Hypothesis
Experiment
Conclusion
(theory or law)
CAN NOT
BE PROVEN
CORRECT!
ONLY
PROVEN
WRONG!
1.3 Scientific Method
•
Understanding the parts
–
Observation
• Qualitative data – descriptive, nonnumeric
information.
– Color, odor, texture, or “hot” and “cold”
• Quantitative data – definite numerical
information.
– 38 C, 24.5 m , or 4.1 1015 Hz
1.3 Scientific Method
– Hypothesis
• Tentative explanation or “educated guess”
– Experiment
• Set of controlled observations
• Independent variable – the variable that will be
changed.
• Dependant variable – the value that changes when
the independent variable changes.
• Constants – the other factors that are not allowed to
change.
• Control – standard used for comparison
1.3 Scientific Method
– Experiment continued
• An experiment is designed to test the
hypothesis that table salt will dissolve faster
in hot water than in room temperature water.
– Independent variable: temperature
– Dependant variable: rate of dissolving
– Constants: amount of salt, water, and stirring
– Control: rate room temp water dissolves
1.3 Scientific Method
– Conclusion
• Theory – tested explanation of WHY something
occurs.
– Einstein’s theory of relativity, Atomic theory,
Kinetic theory, and Quantum theory
– Model – visual, verbal or mathematical
explanation that needs extensive testing to
become a “theory”.
• Law – summary of WHAT will occur.
– Newton’s First Law (gravity) and Law of
Conservation of mass
1.4 Scientific Research
• Pure or Applied Research
– Pure – study just to understand
• When scientists (Molina and Rowland,1974) studied
how CFC’s react to break down ozone, they were
doing pure research.
– Applied – study to use
• When scientists used the CFC/ozone interaction to
explain the thinning of the ozone layer, it became
applied research.
• Technology – practical use of scientific
information.