Post on 28-Dec-2015
Math and Measurement
Unit 2
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Math and Measurement
• Use a lot of math in chemistry
• Learn about the mathematics of science
• Metrics, measurement, manipulating numbers
• Sometimes different than in math class
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Qualitative vs. Quantitative
• Qualitative– Descriptive measurement– Non-numeric– Examples:
• Color• Precipitate• Cold/hot
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Qualitative vs. Quantitative
• Quantitative– Quantity– Numeric– Units….
– NUMBERS ARE MEANINGLESS NUMBERS ARE MEANINGLESS WITHOUT UNITS!WITHOUT UNITS!
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SI Units – System International
• Modified metric used because…– Calculations and measurements are easier– Decimals instead of fractions– Changing units are easier (move the decimal)
– Only Burma, Liberia, and the US don’t use the metric system primarily
– There are 4 SI Units…
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SI Units
• 1. Length – meter (m)– 1/10,000,000 distance from equator to
North Pole– Distance light travels in 1/299,792,458
seconds
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SI Units
• 2. Mass – kilogram (kg)– 1 liter of water at 4oC– 1000 grams (grams are the base unit)
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SI Units
• 3. Time – seconds (s)– 1/86400 of the mean solar day
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SI Units• 4. Volume – liters (L)
– Also expressed as cubic units of length
– 1L = 1000 cm3
– 1 mL = 1 cm3