CHEM103 Module 1
General Chemistry (Portage Learning Online)
messages.pdf_cover_qr_code_label
messages.studocu_not_sponsored_or_endorsed_by_college
messages.downloaded_by
, lOMoARcPSD|64109549
Module I
Monday, January 6, 2025
10:10 AM
Domains of Chemistry
Macroscopic - what you can be seen or sensed directly by human sight
Microscopic - under a microscope or you have to imagine it
Symbolic - specialized language used to represent macroscopic and microscopic domains
what you write, such as equations, formulas, etc.
Measurements
What are the 3 basic parts of a measurement?
A size (a number written in decimal or scientific rotation)
A standard of comparison (a unit)
An indication of uncertainty.
What is the difference between an exact number and an uncertain measurement?
Exact number - derived from counting, uncertain measurement, derived from a measurement other
than counting.
Exact numbers - there is no uncertainty, they are defined or counted.
E.g. a dozen of eggs, 1 foot is exactly 12 inches.
Measurements have inherent uncertainty due to the process.
Results calculated from a measurement are as uncertain as the measurement itself
Determine how many significant figures are in the numbers below:
Significant figures defined: all measured digits in a determination, including the uncertain last digit.
ALL properly measured digits are significant.
Leading zeros are not significant (first)
Captive zeros (in the middle) are significant
Trailing zeros, if there is a decimal they are significant. (last)
Significant zeros in bold
3090
0.008020
1267
55.0 - 3 significant figures
70.607 - 5 significant figures
0.00832407 - 6 significant figures
1300 - 2 significant figures, therefore 1.3 x10 3
1300. - 4 significant figures, therefore 1.300x10 3
1300.00 - 6 significant figures, 1.30000x10 3
Addition or subtraction - round to the same # of decimal places as the least precise value.
Multiplication or division - round to the same # of digits as the least precise value
If less than 5, leave unchanged
messages.downloaded_by