CHEM 121 Chapter Notes - Chapter 0: Kilogram, Microgram, International System Of Units
Document Summary
Mass (defined as amount of matter in an object) Measured in si units by kilograms (kg) Matter (term used to describe anything with physical presence - anything you can touch, taste, or smell) *metric gram, milligram, and microgram are more commonly used. Standard kilogram defined as mass of international prototype kilogram (cylindrical bar of platinum-iridium alloy stored in vault in suburb paris, france. Mass: measure of amount of matter in an object (stay the same wherever you are) Weight: measure of force that gravity exerts on an object (depends on where you are) Meter (m) (standard unit of length in si system) 1790: named one ten-millionth of distance from equator to north pole. 1889: distance between two thin lines on bar of platinum-iridium alloy stored in. 1983: equal to distance traveled by light through vacuum in 1/299,792,458. 10% longer than an english yard and much too large for most measurements in chemistry.
