# Basic question

Jesse J. Parry casshan at siu.edu
Thu Mar 18 00:04:39 EST 1999

```Dima Klenchin <klenchin at facstaff.REMOVE_TO_REPLY.wisc.edu> wrote in message
news:7c66it\$fve\$2 at news.doit.wisc.edu...
>
>Hmm, a number of people did provide the answer.
>
>>However, I
>:would recommend that you find this type of answer in a textbook as it
>:should be very easy to find.
>:
>:a mol is equivalent to 6.02E23 molecules.
>
>I disagree. ;-)
>
>A mole is a measure of quantity defined in such way as to compare absolute
>number of single molecular entities of having different molecular masses.
>Arbitrary, it was taken to be measured in grams (number of them
>equal to the molecular mass). It *happened* (by the design of the our
>universe) that every mol contains ~ 6.02^23 molecules (called Avogadro's
>number - the arbitrary nature of which is clear from the fact
>that it is not whole number, if I remember it correctly).
>
>IMHO, this way of putting it is more logical.
>
>:therefore a mmol is equivalent to 6.02E20 molecules.
>:it refers to an absolute number of molecules.
>:
>:on the other hand, M corresponds to a concentration. That is 6.02E23
>:molecules per liter.
>:
>:therefore a mM concentration is equivalent to 6.02E20 molecules per liter.
>:
>
>Naturally, there is nothing to add here.
>
>        - Dima

How about a reference for this information that you obviously pulled out of