Chem chapter 1

# Chem chapter 1 - The last digit in a measured number is...

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Chem. 9/8/11 Intensive vs. extensive Temp is proportional to the average kinetic energy of a particle Heat conduction Describes flow of heat When hot = molecules are moving around faster Temperature Celsius scale Freezing point at 1 atm: 0 degrees Boiling pt at 1 atm: 100 degrees Kelvin scale The “absolute” scale Lowest temp possible: 0K (absolute zero) Fahrenheit Freezing pt of water at 1 atm: 32 degrees Boiling pt of water at 1 atm: 212 degrees Kinetic energy: K= <1/2 mur^2> = 3/2 kT where T is temperature HINT converting temp on test: Asked to convert a change in temp between initial and final Significant numbers Must put decimal places Uncertainty in measurement Two types of numbers in chemistry Exact numbers Those that have defined values determined by counting Ex. Number of students Inexact number must be reported so as to indicate its uncertainty Significant figures are the meaningful digits in a reported number

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Unformatted text preview: The last digit in a measured number is referred to as an inexact number A number that has traileing zeros where no decimal place is indicated, if meant to represent a measured quantity, is ambiguous, and should instead be written in scientific notation Ex. 5100 g should be written as: 5.1x10^3g or 5.10x10^3g or 5.100x10^3g Rounding Round down if the left most non-significant digit is less than or equal to 4 Round at the very end of the problem Multiplication and Division Result carries the same number of sig figures as the number with the least sig figures Ex. 3.1870x(2.100/10.2)x5 = 3.2807 = 3.28 10.2 has the least number of sig figures therefore answer can only have 3 sig figs. Addition and Subtraction Result carries the same number of decimal places as the number with the least number of decimal places KEEP TRACK OF SIG FIGS FOR EACH STEP DURING CALCULATIONS...
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## This note was uploaded on 01/26/2012 for the course CHEM 307 taught by Professor Several during the Fall '08 term at Rutgers.

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Chem chapter 1 - The last digit in a measured number is...

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