# Measurement - e kg/m 3 frequency cycles/time s-1 hertz(Hz...

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Measurement quantitative observations include 3 pieces of information o magnitude o unit o uncertainty measurements are not numbers o numbers are obtained by counting or by definition; measurements are obtained by comparing an object with a standard "unit" o numbers are exact; measurements are inexact o mathematics is based on numbers; science is based on measurement The SI System Le Systéme Internationale (SI) is a set of units and notations that are standard in science. Four important SI base units (there are others Quantity SI Base Unit English Equivalent length meter (m) 1 m = 39.36 in kilogram (kg) 1 kg = 2.2 lbs second (s) temperature kelvin (K) °F = 1.8( +32 K = °C + 273.15 derived units are built from base units Some SI derived units Quantity Dimensions SI units Common name length × length m 2 square meter length/time m/s mass/volum

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Unformatted text preview: e kg/m 3 frequency cycles/time s-1 hertz (Hz) acceleration velocity/tim e m/s 2 mass × acceleration kg m/s 2 Newton (N) force × distance kg m 2 /s 2 Joule (J) • Prefixes are used to adjust the size of base units Commonly used SI prefixes (there are others Meaning Abbreviati on Exponenti al Notation billion G 10 9 million M 10 6 thousand k 10 3 hundredths of c 10-2 thousandth s of m 10-3 millionths of µ 10-6 billionths of n 10-9 trillionths of p 10-12 • several non-SI units are encountered in chemistry Unit type SI conversion Notes volume 1 L = 1000 cm 3 1 quart = 0.946 L Angstrom length 1 Å = 10-10 m typical radius of an atom mass unit mass 1 u = 1.66054×10-27 kg about the mass of a proton or neutron; also known as a 'dalton' or 'amu'...
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## This note was uploaded on 11/22/2011 for the course CHEMISTRY CHM1025 taught by Professor Laurachoudry during the Fall '10 term at Broward College.

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Measurement - e kg/m 3 frequency cycles/time s-1 hertz(Hz...

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