Errors Chpt 3

# Errors Chpt 3 - sig figs in mantissa = sig figs in number...

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1 Quantitative Chemical Analysis Seventh Edition Quantitative Chemical Analysis Seventh Edition Chapter 3 Experimental Error Copyright © 2007 by W. H. Freeman and Company Daniel C. Harris Daniel C. Harris Random Systematic

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2 0.234 58.3 In experimental data, the first uncertain figure is the last significant figure . 0.234 58.3 significant figure: The number of significant digits in a quantity is the minimum number of digits needed to express the quantity in scientific notation. .
3 Adding and subtracting with sig figs: Keep least sig figs beyond the decimal point 121.795 Adding and subtracting with sig figs: Keep least sig figs beyond the decimal point WATCH OUT: SAME POWERS OF 10! Multiplying and dividing with sig figs: Keep least sig figs. logarithms with sig figs: sig figs. in mantissa = sig figs in number

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4 logarithms with sig figs: sig figs. in mantissa = sig figs in number logarithms with sig figs:

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Unformatted text preview: sig figs. in mantissa = sig figs in number log( 3.39 x 10 2 ) = log( 3.39 ) + log (10 2 ) = 0.530 + 2 = 2. 530 log( 3.39 x 10-5 ) = log( 3.39 ) + log (10-5 ) = 0.530 – 5 = -4. 470 NB 1 sig fig! 5 Propagation of Uncertainty from Random Error Propagation of Uncertainty from Random Error Propagation of Uncertainty from Random Error Th is lik e a d in g s y te m tic r o Propagation of Uncertainty from Random Error 6 Propagation of Uncertainty from Random Error Propagation of Uncertainty from Random Error 7 The real rule: The first uncertain figure is the last significant figure. TIP: In our calculations, we retain extra insignificant digits and round off only at the end. DON’T GIVE MORE SIG FIGS THAN YOUR UNCERTAINTY!!! For systematic uncertainty, we add the uncertainties of each term in a sum or difference....
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## This note was uploaded on 05/19/2010 for the course CHEM 159 taught by Professor De during the Spring '10 term at UCSB.

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Errors Chpt 3 - sig figs in mantissa = sig figs in number...

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