Summary Stoichiometry - mole calcuations

THE MOLE

Revision :




Atomic number (2)
'



always smaller number on Periodic Table ( left side)
.
number of protons in nucleus

a
number of electrons in a neutral atom


Mass number (A)
greater number periodic table ( left side)
'

on

-
number of nucleons (neutrons+ protons)
for
N=B mole calculations round off to nearest whole number
- : →

-


except :
chlorine 35,5
copper 63,5


Relative atomic mass
•

a number that indicates how times heavier atom of an
many an

112
'
element is, compared to the of of the of C- 12
mass mass a
single
atom
•
no unit
•
= A (on periodic table)
'
of the of all the different isotopes of that
weighted
= '
mass
average
•




element
•



weighted average
=
abundance of each isotope in nature is taken into
account



Isotopes
•

Atoms of the same element (same amt of protons) but with different
masses due to different numbers of neutrons


Relative formula mass
-

same as relative atomic mass
,
but for ionic substances
-
add masses of all components

The mole
that quantity of matter containing exactly the number of
elementary
•


same

of C- 12
particles as there are carbon ,
atoms in
12g
specific quantity of particles
'




* 6,02 ✗ 1023 *
.




"
SI unit of amount of substance
•
"


•

unit → mot