CH100 F10 C3 - Chapter 3 Measurement and Chemical...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 3 Measurement and Chemical Calculations Problems 1-15, 27, 33-51, 63-77 3.2 Scientific Notation A method of expressing numbers precisely. Useful for large or small numbers. coefficient exponential a.bc x 10 n The coefficient, a.bc , is a decimal (between 1 and 10). The ‘n’ is an integer. The exponential is 10 or 0.1 (1/10) to the n th power: 10 3 = 10x10x10 = 1,000 10 -3 = = 10 0 = = -9.972 x 10 3 = 3.56 x 10 -3 = 7.33 x 10 0 = *A negative exponent has no relation to the sign of the coefficient*
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
3.5 Significant Figures (SF) Measurements always have an uncertainty. That is, the last digit of a measurement is uncertain. For example, a length measurement of 9.654 m implies 9.654 m + 0.001 m. Or 9.654 m has 3 accurate digits and 1 uncertain digit. When making measurements, one measures one decimal place past the accuracy of the measuring device. For example, given a meter stick (with no gradations), your reported measurement should be to the 0.1 meter.
Background image of page 2
3.5 Significant Figures - 2 The number of significant figures is the number of accurate digits plus the one uncertain digit. How many significant figures are in a measurement? Decimals: Sum the digits from the first non-zero digit to the last digit. Trailing zeros are significant (in a decimal). How may S.F.? 1) 9.654 m ? SF 2) 75.290 m ? SF 3) 0.0075290 m ? SF 4) 0.75290 m ? SF 5) 65,000,000 years ? SF For 5), 8 SF implies we know the number very accurately, i.e., the dinosaurs died out 65,345,242 years ago. If there is no decimal point, trailing zeros may or may not be significant. Scientific Notation: # SF = # digits in coefficient (do not include leading zeros) 1) 6.5 x 10 7 ? SF 2) 6.500 x 10 7 ? SF 3) 6.5345242 x 10 7 ? SF
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Significant Figures-3 Rounding: Reducing the number of SF: If digit dropped is less than 5, leave preceding digit If digit dropped is 5 or greater, increase preceding digit by 1. Round each number to 4 SF
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/29/2011 for the course CHEM 100 taught by Professor Jablonsky during the Spring '11 term at University of Alabama at Birmingham.

Page1 / 18

CH100 F10 C3 - Chapter 3 Measurement and Chemical...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online