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