Empirical Formula Determination
(or some other interesting title of your choice)
A. Student
A. Nother, Partner
October 6, 2009
Purpose:
The goal of this experiment was to (you supply the goal). This was accomplished by
using (supply a brief – one sentence – description of how to achieve the purpose).
Method:
The empirical formula of an ionic compound is the lowest reduced molar ratio of its
components. To find the moles of each component of a compound we need to know the
mass of each species present. In this experiment we combined two pure elemental
substances into a new compound – we actually did this twice in order to prepare two
different compounds. In the first case we combined (fill in with your own words here to
explain what you did in Part I). In the second part of the experiment we attempted to
make (again, complete this with your own words). To determine the mole ratio for each
compound we collected various mass data so that we can determine, first, the mass of
each element present in the compounds. These elemental masses can be converted (fill in
the rest of the story here).
Part I Data: (Be sure to include units in this table. Delete this note after reading it.)
YOUR DATA
Mass of evaporating dish
Mass of evaporating dish and zinc
Mass of evaporating dish and compound
OTHER GROUP’S
DATA
Part I Calculations: (Use the equation editor to insert the appropriate equation used for
each calculation and an example using your data. Delete this note after doing so.)
MASS OF ZINC
EQUATION
EXAMPLE USING YOUR DATA
MZn = Mdish w/ Zn – Mdish
MZn = X – Y g = Z g
Mcompound = Mdish w/ compound – Mdish
MASS OF COMPOUND
MASS OF CHLORINE
moles Zn 
MOLES OF ZINC
M Zn
Molar Mass Zn
moles Zn 
Zg
 ? mol
g
65.38 mol
MOLES OF CHLORINE
MOLE RATIO
mole ratio 
moles Zn
moles Cl
mole ratio 
moles Zn ?
 ?
moles Cl ?
Part I Results: (Be sure to include units in this table of results. Delete this note after
reading it.)
YOUR DATA
Mass of zinc
Mass of compound
Mass of chlorine
Moles of zinc
Moles of chlorine
OTHER GROUP’S
DATA
Mole ratio
Empirical formula
Part II Data:
YOUR DATA
OTHER GROUP’S
DATA
Mass of crucible and lid
Mass of crucible, lid, and copper
Mass of crucible, lid, and compound
Part II Calculations:
EQUATION
MASS OF COPPER
MASS OF COMPOUND
MASS OF SULFUR
MOLES OF COPPER
MOLES OF SULFUR
EXAMPLE USING YOUR DATA
MOLE RATIO
Part II Results:
YOUR DATA
OTHER GROUP’S
DATA
Mass of copper
Mass of compound
Mass of sulfur
Moles of copper
Moles of sulfur
Mole ratio
Empirical formula
Discussion:
Examining the results, we see that our formulas for zinc chloride and copper sulfide were
(supply your opinion based on your results). (Continue with an explanation of what
might have caused any errors. Address the discussion points outlined on pages 35 – 36
of the lab manual. Comment on how you might change the experiment, if you were to
repeat it, so that you can get more a more accurate result.)