Use of Units by Nick Ragusa

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Use of Units
by Nick Ragusa (Class of 2001)

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Use of Units In Chemistry

The system of measurements in chemistry and science is called the International System, often referred to as the SI. You may have noticed the symbol for International System is switched it’s not IS because the symbol comes from the French Le Systeme International d’ Unites. Every book and scientist you meet will use SI base units.

Below is a chart of the SI base units:

S.I. BASE UNITS
Quantity	Name	Symbol
Length	meter	m
Mass	gram	g
Time	second	s
Amount	mole	mol
Temperature	Kelvin	K

In the International System, prefixes are commonly added to easily obtain larger and/or smaller quantities. These are the SI prefixes and are necessary to continue chemistry.

Below is a chart of the SI prefix units you need to know:

S.I. PREFIXES
Prefix	Symbol	Amount
mega	M	1,000,000
kilo	k	1,000
hecto	h	100
deca	da	10
deci	d	0.1
centi	c	0.01
milli	m	0.001
micro	u	0.000001

Below is a basic conversion chart of common units:

CONVERSIONS OF METERS*
1000 millimeters	=	1 meter*
100 centimeters	=	1 meter*
10 decimeters	=	1 meter*
10 meters	=	1 decameter*
100 meters	=	1 hectometer*
1000 meters	=	1 kilometer*

*the unit meters may be replaced with liters or grams.

During labs, homework assignments, tests, and real life you will not always be given the SI units you may be given another unit.

Other units are given below(SI units are given in bold):

Other Conversions
Time
60 seconds	=	1 minute
60 minutes	=	1 hour
Temperature
1 Kelvin	=	1^o Celsius
Pressure
1 atmosphere	=	760 mm of Hg
1 atmosphere	=	101.3 kpa
1 atmosphere	=	760 Torr

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