# Dimensions, Units, And Symbols

Notice the symbols of the dimensions as they would be used in formulas. The basic metric symbol or the symbol of the most used metric unit is listed after the metric units.

 DIMENSION SYMBOL METRIC UNITS SYMBOL 'ENGLISH' UNITS LENGTH S, l, d, r meter (+m.p.) m Ft, in,Yd, mi, etc. AREA A sq.meter, etc,hectare m2 sq.Ft, etc., acre VOLUME V cu.meter, etc., liter m3, L cu.Ft,cu.in,etc.,gal,Floz. TIME t sec (+m.p.) sec,min,hr,day,yr,etc.(both metric & English) MASS m Kilogram (+ m.p.), AMU kg (slug, rarely used) FORCE (weight) F, Fw Newton (+ m.p.) N Pound (#), Oz, etc. VELOCITY v meter/sec,KPH,etc m/sec Ft/sec, MPH, etc. ACCELERATION a meter/sec.sq., etc. m/sec2. Ft/sec sq., etc. PRESSURE P N/sq.m, atm.,Pa atm,Pa* #/sq.in (PSI), inHg, etc. DENSITY D g/cc, Kg/liter, etc. g/cc #/cu.Ft, #/gal, etc. TEMPERATURE T Celsius or Kelvin °C or K Fahrenheit or Rankine ENERGY E Joule (+ m.p.) J foot-pound HEAT Q calorie (+ m.p.) cal BTU (British Thermal Unit) CONCENTRATION C** gram/L, mol/L, Molar M (#/gal or #/cu.ft, rare)

Abbreviations: Ft = foot, in = inch, AMU = atomic mass unit, KPH = kilometers per hour, MPH = miles per hour,
gal = gallon, PSI = pounds per square inch, cc = cubic centimeter, inHg = inches of mercury, Pa = Pascal
m.p. = metric prefixes, cu. = cubic, sq. = square, atm = atmosphere.

*The unit Pa, for Pascal, is a unit of pressure that is the standard unit for the SI system, the MKS system in the metric measurements. The unit of Pascal, however, is rarely used in chemistry. Instead, the unit "atm," for "atmosphere," is still most used in chemistry.
**The symbol "B" is now the official symbol for concentration in the SI, but there are still chemistry texts using the "C" as is shown here."

The table above lists almost all the dimensions you will need in this course, the symbol for each dimension as it will be used in common formulas, and the units of each dimension. Most chemistry texts will use the MKS system (meter, kilogram, second) rather than the less-used CGS (centimeter, gram, second) system. A system is defined by its basic measure of distance, mass, and time.We will use the MKS system, also called the S.I., or International System. The symbol for only the basic unit of each dimension in the metric system is on the list.

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