# Thelastdigitistheestimatedone

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Unformatted text preview: 0,000 by 0.006 3x104 3 [4­(­3)] = x10 = 0.5x107 = 5x106 ­3 6x10 6 7 Physical Science 1 Chapter 1 Follow­up Problems: 1. (5.5 x 10 3 ) (3.1 x 10 5 ) = 2. (9.7 x10 14 )(4.3 x10 ­20 ) = 3. 6 2.6x10 = 2 5.8x10 4. ­ 1.7x10 5 = ­ 8.2x10 8 5. (3.7x 10 ­6 ) x (4.0 x 10 8 ) = 8 Physical Science 1 Chapter 1 SIGNIFICANT FIGURES Two kinds of numbers are used in science: · Counted or Defined: exact numbers; no uncertainty · Measured: are subject to error; have uncertainty Uncertainty in Measurements: · Every measurement has uncertainty because of instrument limitations and human error. · The last digit is the estimated one. · Significant numbers are the certain and uncertain digits. 9 Physical Science 1 Chapter 1 Significant Figure Rules Not significant Zero used for “cosmetic” purposes Not significant Zero used to position decimal Significant All zeros between non­ zero digits 0 . 0 0 4 0 0 4 5 0 0 Significant All non­zero digits Significant Zeros to the end of a number and right of decimal point Examples: Determine the number of significant figures in each of the following measurements: 461 cm 93.500 g 1025 g 0.006 m 0.705 mL 5500 km Rounding Off Rules 1. If the rounded digit is <5, the digit is simply dropped. 2. If the rounded digit is ³5, the...
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## This document was uploaded on 03/18/2014 for the course CHEM 322 at Los Angeles Mission College.

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