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Unformatted text preview: wer is sensible.
EXCEPTIONS TO ROUNDING:
Some numbers are accurate by DEFINITION.
For example: a dozen = 12. Exactly. No exceptions.
When using these numbers in your calculations, IGNORE how many significant figures they have.
Treat them as if they were infinitely accurate.
Some numbers are defined as infinitely accurate:
For example 1 inch = 2.54cm exactly. Treat it like it was 2.54000000….
Others will be pointed out to you as the need arises.
Density
PHYSICAL property: Can be used to distinguish two substances (e.g., alcohol and water).
Density = MASS divided by VOLUME.
The DENSITY OF WATER IS 1g/ml
Density of Gases << Density of Liquids < Density of Solids
units include: g/mL, kg/mL, lb/pint, mg/cc
Density of Odd Shaped Solids
Mass: use a scale
Volume: can calculate for a regular shape.
For an irregular shape use the ARCHIMEDES principle:
An object that sinks in water displaces a volume of water equal to its own volume. Density of Coke vs. Diet Coke: Demo to be done in class....
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 Spring '08
 walker
 Chemistry

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