Various Units and Dimensions Commonly used in Chemical Engg

Introduction with Units and Dimensions 

Dimensions: Theses area basic concepts of measurements like Length, mass, time, temperature and so on. 

 Units : It express the Dimensions like length in meter, centimetre and millimetre and may more, similarly time can be expressed in  second, minutes, hour, day etc 

Therefore we required a fundamental units which will not be effected by any mathematical operation, doesn't effected by formulas and doesn't effected with time. Easy to use will some logical approach.

We have various types of system of units 

1.  Fundamental units 2. Derived units 

Fundamental units are:

1.     CGS (centimetre gram second)

2.     MKS (meter gram second)

3.     FPS (foot pound second)

4.     SI (le systeme internationale)

5.     AE (American engineering system )

Derived unites are those which are generated with the help of fundamental units.

Let’s have some examples:

Physical quantity	Name of units	Symbols	System
Length	Meter	m	SI
	Centimetre	cm	CGS
	foot	ft	FPS (A.E)
	Inch	in
Mass	kilogram	kg	SI
	Pound	lbm	A.E
	Milligram	mg
Time	Seconds	s	SI
	Minutes	m
	Hours	h
Temperature	kelvin	k	SI
	fahrenheit	oF	AE
	Celsius	Degree C
Molar amount	Mole	mol	SI
Energy	joule	J
	British thermal unit	Btu,(ft)(lbf)	AE
force	newton	N	SI
	Pound(force)	lbf	AE
power	watt	W	SI
	horsepower	hp	AE

Prefixes used in SI system:

Factor	Prefix	symbol
109	giga	G
106	mega	M
103	kilo	k
102	hecto	h
101	deka	da
10-1	deci	d
10-2	centi	c
10-3	Mili	m
10-6	micro	µ
10-9	nano	n

These are some basic units and its system which mush be remember by under graduate student. In next blog we will study some example in detail.

Written by :

Prince Bhatti 

Chemical Engineer

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@prince bhatti: Any data written on the blog is not responsible for its use for education purposes.