CHEM 100

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CHEM 100 Chemistry and Society Winter Quarter
2008 SCCC Lecture 39
Now we have a little time to look at some of what
we have covered previously..
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• We have looked at how to tackle several different
  types of questions
• questions where you are asked to explain a
  concept.
• multiple choice questions.
• designing an experiment to find something out
  about a system.
• calculate a particular quantity.

To do well in this course you need to be able to
answer all these kinds of questions effectively.
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• Identify each of the following substances as
  either an element or compound.
• Sugar
• Carbon
• Lead
• Rust

(a) compound, (b) element, (c) element and (d)
compound
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• Which formula below corresponds to the compound
  containing one magnesium atom, one sulfur atom
  and four oxygen atoms? What is the name of this
  compound?
• So3PO4
• MgSO4
• MgSuO4
• MgSO4

(d) MgSO4 the name of this compound is magnesium
sulfate.
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• Write the prefix for multiplying by each of the
  numbers below
• 0.01
• 1,000,000
• 0.000001

• x 10-2 centi
• x 106 mega
• x 10-6 micro

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Explain the scientific method

• There are three main steps in the scientific
  method
• perform experiments on system and record
  observations.
• analyze data and propose hypothesis to explain
  results of experiments.
• perform additional experiments to test
  hypothesis.
• If our additional experiments confirm hypothesis
  the hypothesis becomes a theory. If not we must
  revise our hypothesis and perform additional
  experiments to test it. The process continues
  until our hypothesis and experiments agree.

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• Place the following scientists in chronological
  order of their contribution to atomic theory
• Lavoisier
• Democritus
• Dalton
• J. J. Thompson

(b) (a) (c) and (d)
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Can a theory be disproved
A theory can be disproved if experimental data is
shown to be in disagreement with it.
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What type of elements form covalent compounds
Covalent compounds generally form between
non-metals with that do not have very large
differences in electronegativity.
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What is a polyatomic ion? Provide several
examples
Polyatomic ions are ions composed of more than
one atom. Examples include NH4, CN-, SO42- and
CO32-.
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There will be class on Monday and Tuesday next
week. We will mainly be doing practice problems
in class so this is a very good chance to get
some exam revision done.