Basic Chemistry Concepts

Science ¡V the study of the universe
Chemistry ¡V the study of matter and its changes
Scientific disciplines (ex. Chemistry, geology, physics, botany)
Subdisciplines (general, inorganic, organic, analytical, physical, environmental)

Technology: the application of scientific knowledge to the production of new products to improve human survival, comfort, and quality of life

Scientific Method
1. ask a question
2. observation (collect data)
3. hypothesis (educated guess)
4. experimentation
5. analyze results
6. conclusion
7. communicate your results

Hypothesis ¡V specific yet tentative guess
Theory ¡V less tentative; hypothesis that has been tested repeatedly

Precision vs. Accuracy
Precision: how close a series of measurements on the same object are to each other
Accuracy: how close a measurement comes to a true or accepted value

Uncertainty in measurements (in any measurement, the last digit reflects the uncertainty)

Significant digits
ƒÞ All non zero digits (1-9) always significant
ƒÞ Leading zeros (placeholders) not significant
ƒÞ Trailing zeros only significant when there is a decimal point.

Rounding ¡V Odd/even/5 Rule ¡V
Look at the number before the 5 and round to the nearest even number.

Operational Rules ¡V Significant digits
1.   Multiplication and Division ¡V use fewest number of sig figs in the problem
2.   Addition and Subtraction ¡V round to the place of greatest uncertainty

When doing a problem with only multiplication/division ¡V round answer at the end.  

If you are doing combination of mult./div. and addition/subtraction,
round answer before switching types of operations!

Metric System (S.I. system) based on ¡§10¡¨
Composed of base units and prefixes
Base units Length ¡V meter
Mass ¡V gram
Area ¡V m2
Volume ¡V m3 or Liters

Prefixes Kilo (k)   --   103
Centi (c)   --   10-2
Milli (m)   --     10-3
Nano (n)   --     10-9

Be careful!   Units do... [continues]

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