“What do you call a bunch of bad chemistry students?”/“Molasses.”

Various chemistry jokes have “molasses” (mole + asses) in the punchlines. “Q: If a mole of moles were digging a mole of holes, what would you see? A: A mole of molasses” has been cited in print since at least 2002.
 
“What do you call a bunch of bad chemistry students? Molasses!” was posted on Twitter on January 19, 2016.
   
“Molasses—what do they do with the rest of the mole?” and “What do you call 6.02 * 10^23 butts?”/“Molasses” are related jokes.
 
     
Wiktionary: mole
Noun
mole ‎(plural moles)
1. (chemistry, physics) In the International System of Units, the base unit of amount of substance; the amount of substance of a system which contains as many elementary entities (atoms, ions, molecules, etc.) as there are atoms in 0.012 kg of carbon-12. Symbol: mol. The number of atoms is known as Avogadro’s number. [from 1897]
     
Jupiter Scientific (August 4, 2002)
Chemistry Jokes
(...)
Chemistry Joke 19:
Q: If a mole of moles were digging a mole of holes, what would you see?
A: A mole of molasses.
See explanation
Chemistry 19: A mole is used as a count for atoms and molecules. “Molasses” should be read as “mole asses”. 
 
Twitter
SnakeLady
‏@snakelady
StolenFromMichaelRowland: If you come upon a field with a mole of moles digging a mole of holes what is it that you see? A mole of molasses!
3:33 PM - 25 Mar 2009
 
Google Groups: CDE-LHS_ChemistryIsFun
jokes
john daniel decena
2/28/12
(...)
Chemistry Joke 19:
Q: If a mole of moles were digging a mole of holes, what would you
see?
A: A mole of molasses.
 
Twitter
John Thompson
‏@jhnthmpsn
It was great seeing the former chemistry students/characters at the golf course today.  #molasses
5:11 PM - 9 Jun 2012
 
Twitter
Caroline Potter
‏@CMMichelle
“What do you call when you see a moles back?
A little molasses!”
-mrs McReynolds! #happymoleday #molejokes #chemistry
8:59 AM - 23 Oct 2012
 
Twitter
Colton Green
‏@Coltigreen7
@brinnn_ I guess we just know what you call a mole of moles, digging a mole of holes? A: A mole of molasses! -chemistry jokes 😂
7:41 PM - 17 Oct 2013
 
My Town Tutors
Top Mole Day Jokes: 101 Mole Day Jokes
Posted on October 14, 2014 by mmolloy
(...)
8. If a mole of moles were digging a mole of holes, what would you see?… A mole of molasses!
(...)
52. What did Avogadro have on his pancakes?… moleasses
(...)
68. Why did people say Avogadro was lazy?… They said he was slow as moleasses
 
Twitter
J Hizzle
‏@jessiehofficial
“What do you call a bunch of bad chemistry students? Molasses!”
thanks kevin but #ClassicJokeWednesday is tomorrow
10:17 AM - 19 Jan 2016