An MKS System of Units for Chemists The MKS system of units has been very suceeasful in physics and is almost universally adopted today. It would seem worth investigating whether the MKS system would be useful in chemistry and whether it could he introduced without neoessitating the discard of ofdell-established chemical unite. The fundamental chemical unit is, of course, the mole. Gram atomic and molecular weights are obviously not MKS. A new unit that could be called the kilomole (abbr. kmol), equal to 1000 moles, ia needed. The definition retains the use of conventional atomic weights, interpreting them in kilograms, the MKS unit of mass. If a kiloliter (abbr. k l ) is defined as a thousand liters, molarity is kilomoles/kiloliter as well ss moles/liter, millimoles/milliliter, etc. Similarly, a kilomole of an ideal eas would oceuov 22.414 kiloliters at STP. \Vhik the nhovc rhcm>c>Ih I K 5 uuita d amount xurl nn.crnlrnrion work out sltnply, a dungr ~ i ~hIKS t r y . unit ( s f vh~rgei~ thr ~ o u h m ~ h'1.nklng is rquirpd i n ~ I ~ ~ ~ t m r I ~ r nTItc . i.ilot~plri~al~nla ns a rh-mi.d >IKS unit and wnting Famday's cm~hiwrll;tn as the units of 5 become coulombs/kiloequivalent and its numerical value 9.6494 X lo', 1000 times larger than its familiar value. The MKS unit of potential is the joule. In the equation expressing AG in joules, q in coulombs, & in volts, and J in kiloequivalents would be uniformly MKS. However the seele could be reduced consistently by measuring AG in millijoules, q in millicoulombs, J in equivalents, and 5 in millicoulomhs/equivdent (still 9.6494 X 10'). & must remain in volts since it is an intensive property and a millicoulomb-volt would he a millijoule. The author hopes that te~ehersand textbook writers will give serious consideration to the idea of MKS units for chemistry.
Volume 41, Number 1 7, November 1964
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