CHMY 121IN Lecture 4 Outline of Last LectureUncertainty- numbers associated with any measured value- Lies within the last recorded digit - comes from possible error when measuring with equipmento Examples 2.5 cm(5 in an uncertain number) +-.1cm 2.52 cm(2 is an uncertain number) +-.01 cmSignificant Figures- Number of digits in a reported number- Reveals information regarding uncertainty- Leading zeros are NOT counted as Sig Figs- Trailing zeros are only counted if after a decimal pointo Examples 10.586 has 5 Sig Figs 7.8 has 2 Sig Figs 0.0035 has 2 Sig Figs 250 has 2 Sig Figs 7.80 has 3 Sig FigsScientific Notation- A x 10^x -> 1.2 x10^2 -> 120o 2 sig figs- 4.6x10^-4-> 0.00046Rules for Sig Figs- +/-o 46.00 lbs -->2 - 3.64 lbs -->3 49.64 lbs needs to be 3 sig figs49.6 lbs - x/divideo 230 books → 2 x 3.64 lbs/book → 3847.2 needs 3 sig figs847These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Current LectureGiving numbers meaningCommon ConversionsPhysical quantity Name of Unt AbbreviationLength Meter mMass Kilogram KgTime second sTemperature Kelvin KAmount of Substance Mole MolGreek PrefixesKilo- (k) one thousandDeci- (d) one-tenthCenti- (c) one-hundredthMilli- (m) one-thousandthMicro- ( ) one-millionthNano- (n) one-billionth**** These conversions are correct and do NOT affect Sig Figs**** 1 tsp= 0.000005 m^3Examples of Metric/English/ SI conversions- Temperatureo SI unit is the Kelvin (K, not in degrees)o Kelvin is the absolute temperature scaleo Other units include Celsius and Fahrenheito Conversion between the Celsius and Fahrenheit F=32+ 9/5(C) or C= 5/9(F-32)o Conversion between Celsius and Kelvin K=C+273.15 or
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