Chapter 3 PPt In Class Presentation

# Chapter 3 PPt In - Precision and Accuracy Think of a Dart Board Precision is the closeness of a set of values obtained from identical

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1 Precision and Accuracy - Think of a Dart Board!!! Precision is the closeness of a set of values obtained from identical measurements (are your darts clustered??)

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2 Accuracy is the closeness of a single measurement to the true value (the bulls-eye!) Precision vs. Accuracy Draw the Dart Board Showing Each of These: good precision & good accuracy poor accuracy but good precision good accuracy but poor precision Precision & Accuracy Compared
3 The DREADED “Significant Figures” Those digits in a measured number that include all certain digits and final one have some uncertainty Rules for assigning significance to a digit: 1. Digits other than zero are always significant. 2. Rules about zeros: Final zeros after a decimal point are always significant. Zeros between two other significant digits are always significant. Zeros used only to space the decimal are never significant. Determine the number of significant digits in each of these: 6.751 g 0.157 kg 28.0 ml 2500 m 0.070 g 30.07 g 0.0067 cm 6.02 x 10 23 atoms Scientific notation!!!

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4 A)Between 0 and 2 in b)Between 1 and 2 in C)Between 1.5 and 1.6 in D)Between 1.54 and 1.56 in E)Between 1.546 and 1.547 in Which of the following best describes the length of the
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## This note was uploaded on 01/12/2012 for the course CHEM 103 taught by Professor Jeffashley during the Fall '10 term at Philadelphia.

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Chapter 3 PPt In - Precision and Accuracy Think of a Dart Board Precision is the closeness of a set of values obtained from identical

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