sigfigs02

# sigfigs02 - CHM 235 Dr Skrabal Significant Figures...

This preview shows pages 1–4. Sign up to view the full content.

Significant Figures • Definition: Minimum # of digits needed to express a number in scientific notation without a loss of accuracy • Example: Partial pressure of CO 2 in atmosphere 0.000356 atm. This number has 3 sig. figs., but leading zeros are only place-keepers and can cause some confusion. So express in scientific notation: 3.56 x 10 -4 atm This is much less ambiguous, as the 3 sig. figs. are clearly shown. CHM 235 - Dr. Skrabal

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

View Full Document
Avoiding ambiguity • Consider the quantity 1000 g . A little ambiguous—how many sig. figs. are intended to be in this number? 1.000 x 10 3 g (4 sf) 1.00 x 10 3 g (3 sf) 1.0 x 10 3 g (2 sf) 1 x 10 3 g (1 sf) • Using scientific notation takes away the ambiguity.
Rules for using sig. figs. in calculations • Addition and Subtraction – Answer goes to the same decimal place as the individual number containing the fewest number of sig. figs. to the right of decimal point. Example of addition: Formula weight of PbS: 207.2 + 32.066 = 239.266 b round to 239.3 Example of subtraction: 4.5237 – 1.06 = 3.4637 b round to 3.46

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 02/09/2012 for the course CHEMISTRY 101 taught by Professor Endy during the Spring '11 term at Harvard.

### Page1 / 12

sigfigs02 - CHM 235 Dr Skrabal Significant Figures...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online