SI System of Measurement (known commonly as the metric system)
Background The English system of measurement originated in 1215 with the signing of the Magna Carta. It attempted to bring uniform measurements to world trade. In 1790, the French government appointed a committee of scientists to develop a universal measuring system.
It took ~10 years, and they unveiled the metric system. Property. Unit It took ~10 years, and they unveiled the metric system. Property Unit abreviation length meter m mass gram g volume liter L time second s quantity of matter mole mol
The International System of Units (Systeme International d’unites) was developed in 1960 from the older system. It is the world’s most widely used system of units, both in commerce and science. A notable exception is the United States, which still uses many old units in addition to SI.
SI Base Units in Chemistry Quantity Name Symbol length meter m mass kilogram kg time second s amount of substance mole mol temperature Kelvin K
Prefixes in the SI System Prefix Prefixes in the SI System Prefix x base unit Symbol equals base units Sci. notation Mega- dollar 1 Md = 1,000,000 dollars = 1x 106 kilo- dollar 1kd = 1,000 dollars = 1x 103 hecto- dollar 1 hd = 100 dollars = 1x 102 deka- dollar 1 dad = 10 dollars = 1x 101 dollar 1 dollar = 1 dollar = 1x 100 base unit equals prefix x base unit Symbol Sci. notation 1 dollar = deci-dollars 10 dd 1x 101 1 dollar = centi-dollars 100 cd 1x 102 1 dollar = milli-dollars 1 000 md 1x 103 1 dollar = micro-dollars 1 000 000 µd 1x 106 1 dollar = nano-dollars 1 000 000 000 nd 1x 109
Conversion of SI Units Use equivalencies to convert units Conversion of SI Units Use equivalencies to convert units. Always make the bigger unit 1 and convert back to the base unit. M k h da - d c m µ n
For example: 3 km ______m___________cm__= ____ cm km m
3 km 1000 m 100 cm = 300 000 cm 1 km 1 m s.n.= 3 x 105 cm
Likewise: 2. 5 mm 1 m 1 dam =. 00025 dam 1 000 mm 10 m. s. n. = 2 Likewise: 2.5 mm 1 m 1 dam = .00025 dam 1 000 mm 10 m s.n.= 2.5 x 10-4 dam
Try this one ! Convert 2.5 dg_______________= ___________ng