Chemistry Notes Chapter 1

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Chemistry Notes Chapter 1

• Intro To Chemistry

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The Ozone Layer

• A chemical is any substance that has definite
  composition.
• Ozone is a substance that is made up of three
  oxygen atoms.
• The Earths atmosphere is divided into different
  layers.
• The troposphere is the lowest layer that contains
  the air that we breathe.
• The stratosphere is the next layer that contains
  ozone that protects us from UV radiation.

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The Ozone Layer

• Ozone is formed when oxygen is exposed to UV
  radiation in the upper regions of the
  stratosphere.
• The energy of the UV rays breaks down oxygen gas
  (O2) into single atoms of oxygen which then
  recombines with oxygen gases to form ozone (O3).
• Ozone can also break down to form oxygen gas,
  creating a balance between ozone and oxygen gas
  in the stratosphere.
• Ozone forms near the equator where the rays from
  the sun are the strongest and then air currents
  distribute it around the globe.

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Chlorofluorocarbons

• Chlorofluorocarbons or (CFCs) are chemicals that
  consist of chlorine, fluorine, and carbon.
• All CFCs are man made and do not occur
  naturally.
• CFCs can break down ozone in the stratosphere
  causing this protective cover to become thinner
  and allow more UV radiation to bombard the Earths
  surface.

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Chemistry

• Chemistry is the study of matter and the changes
  that it undergoes.
• Matter is anything that has mass and takes up
  space.
• Mass is a measurement that reflects the amount of
  matter in a substance.
• Weight is a measure of the amount of matter and
  the gravitational pull on that matter.

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Chemistry Continued

• Chemistry is often broken down into five
  different categories.
• Organic Chemistry, which studies most carbon
  containing compounds.
• Inorganic chemistry, which studies matter that
  does not contain carbon.
• Physical chemistry, which studies the behavior
  and changes of matter and the related energy
  changes.
• Analytical Chemistry which studies the components
  and composition of substances.
• Biochemistry, which studies matter and processes
  of living organisms.

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The Scientific Method

• The Scientific Method is a Systematic Approach
  used in scientific study to do research.
• There are 6 basic steps in the scientific method.
• Observe and state the problem
• Form Hypotheses
• Test hypothesis
• Gather and analyze data.
• Form conclusion
• Retest

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Scientific Study

• Scientific study usually begins with an
  observation.
• Qualitative data is information that describes
  color, shape, odor, or some other physical
  characteristic.
• Quantitative data is numerical information that
  tells you about something using numbers as a
  reference.
• A Hypothesis is a tentative explanation for what
  has been observed. (It is an educated guess)

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Scientific Study Continued

• An experiment is a set of controlled observations
  that test the hypothesis.
• The scientists must carefully plan and set up one
  or more experiments in order to change and test
  only one variable at a time.

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Scientific Study Continued

• A variable is a quantity or condition that can
  be changed in an experiment.
• The variable that you plan to change in an
  experiment is called the independent variable.
• The variable that changes in response to the
  independent variable is called the dependent
  variable.
• You can control the way the independent variable
  changes but the dependant variable you have no
  control over.

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Scientific Study Continued

• A control is a standard used for comparison.
• It shows what your independent variable is
  actually doing.
• A conclusion, is a judgment based on the
  information obtained in an experiment.
• A theory, is an explanation that has been
  supported by many experiments.
• A theory states a broad principle of nature that
  has been supported over time.
• All theories are still subject to new
  experimental data meaning that they may be
  modified or changed.

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Types of Scientific Investigation

• Pure research, seeks to gain knowledge for the
  sake of knowledge itself.
• Applied research is the research undertaken to
  solve a specific problem, or for the advancement
  of technology.
• Technology is the practical use of scientific
  information, for the advancement of human life.