International Conference of Chemical Education, ROME, July 2012

1. Counting chemical
concepts
(dismissing the mole concept)
Alfredo Tifi
Istituto Tecnico Tecnologico “E. Divini”,
San Severino Marche, ITALY
a.tifi@divini.org
ICCE – ECRICE Rome, July 19° 2012

2. Are the moles as simple as
the apples in a kilogram?
what seems to be “logical” is really the product
of pieces of socially validated
utterances, experiences and sensory-motor

3. counting
from sequencing words to evaluating sizes
Ordered-number signs Amount-number signs
(ORDINAL NUMBERS) (CARDINAL NUMBERS)
spontaneous-everyday concepts are
very different from scientific concepts

4. Are the moles as simple as
the apples in a kilogram?
The answer is NO if you want relate
understanding of MOLE to other scientific
concepts as molar mass, Avogadro's
constant, atomic mass unit, actual and
relative atom mass and number.
The response is YES if you settle for
spontaneous use of the concept of
Relative Number of Atoms (Units)

5. Objective
to prepare the spontaneous machinery
to calculate numerical amounts of
atoms or other units at the atomic
level, without (or before) introducing
the mole concept.

7. Number, m
number of
easure of
objects
weight
2nd GRADE 4th GRADE

8. Mole as system of scientific concepts
total
MOLAR number Avogadro's
MASS Number
MOLE
The mole is simply AMU Atomic
the amount of
substance of a system Weight
which contains as
many elementary
entities as there are + Carbon-12
atoms in 0.012 + Total mass
kilogram of carbon 12
+ Amount of Substance
+ number of moles
+ atomic weight in grams

9. Relative number of unities as a
spontaneous concept
relative total mass of atoms
number =
of atoms relative atomic mass
1st Gr. Secondary school

10. Stoichiometric basic calculus
Mass of Mass of
substance A
? substance B
Relative Relative
Number of or multiple Number of
A units B units

11. Applying the spontaneous concept of
RELATIVE NUMBER OF ATOMS

13. RESULTS
• All students in the class mastered this simple
calculations. The relative number of atoms-
formulas-molecules-ions was really
internalized as a cardinal number of
objects, and this was completely different
from the variable “moles” that is almost never
taken as a measure of numerical amount of
substance, notwithstanding our efforts to
vehicle it from the correct academic
definition.

14. CONCLUSIONS
“Scientific/academic concepts can arise
in the child’s head only on the
foundation provided by the lower and
more elementary forms of
generalization which previously
existed.”
Lev. S. Vygotsky (1987, p.177)
L. S. Vygotsky, 1987 The Collected Works of L. S.Vygotsky, Vol I. Problems of general psychology, R.
W.Rieber and A. S. Carton (Eds.). New York: International Publishers.

15. THANK YOU FOR YOUR
ATTENTION
• Alfredo Tifi,
• ITT “E.Divini” San Severino Marche, ITALY
a.tifi@divini.org