# Basic question

Hiranya S. Roychowdhury hroychow at NMSU.EDU
Thu Mar 18 11:57:18 EST 1999

```At 11:04 PM 3/17/99 -0600, Jesse J. Parry wrote:
>
>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

This is really outrageous! You NEED a REFERENCE for the information?

As you yourself pointed out, it comes from a text book. However, I'm almost
sure that some of us do not have to open this basic "text book" to explain
the relationships between "mole" "molar" "Avogdrao's number" and "molar
equivalent".
But, if you must have it... just grab any basic (inorganic) chemistry text
book and go through the chapters on physical chemistry, molecules etc.

Dr. Hiranya Sankar Roychowdhury
GENE LAB/ EPPWS
New Mexico State University
Las Cruces, NM 88003
Ph. (505) 646-5785
hroychow at nmsu.edu

```