Chemistry is the study
of matter.
Matter is anything that
has mass and occupies
space.
1
2
3
4
5
When looking at diagrams like the ones
above ask the following questions.
Are all the atoms the same?
Yes
No
It must be an
element
Are the molecules
identical?
Yes
No
compound mixture
Elements are pure substances
which cannot be broken down by
simple chemical means into
anything simpler.
There are approximately 92
different elements found on earth.
All matter is composed of
combinations of these elements.
Compounds are pure substances
which are composed of 2 or more
elements combined in fixed ratios by
mass.
Mixtures are combinations of
elements and compounds combined in
variable ratios.
Table salt (sodium chloride) is a
compound and sea water is a mixture.
Most compounds names end in ide, ite or
ate
Using the 2 questions
previously given
identify the following
as Elements,
Compounds or
Mixtures and
Determine
A - the total number of atoms
B – The number of different
kinds of atoms
C – the total number of
molecules
D – the number of different
kinds of molecules
1
2
3
4
5
6
7
8
9
11
10
12
13
15
14
16
17
18
19
20
21
22
23
24
Writing Formulas
If the molecular model is
Notice
the the same
Keep
in mind
elementcould
furthest
molecule
appear as
left in the
periodic chart is
written first. If
they're in the Oxygen atom
Hydrogen atom
same column, the
one further down
goes 1st
The formula is
H2O
Write Formulas
for each of the
following
The
formula
is
PCl3
phosphorus atom
chlorine atom
The
formula
is
CO2
Carbon atom
oxygen atom
The
formula
is
CF4
carbon atom
fluorine atom
The
formula
is
S2Br2
sulfur atom
bromine atom
Use the legend to
write a formula for
each of the
following
Use the legend to write a formula for each of the following
1
2
aluminum
bromine
chlorine
carbon
3
4
fluorine
nitrogen
5
6
carbon
silicon
fluorine
7
iodine
bromine
8
silicon
hydrogen
phosphorus
Draw diagrams for the
following formulae
MnSO4
Ca3P2
K 2S
AlPO3
Sometimes the
diagram will contain 2
or more molecules.
In these cases this is
how to adjust the
formula.
The
formula
is Coefficient
3C2I4
carbon atom
iodine atom
The formula
is
Phosphorus atom
2H3PO4
hydrogen atom
oxygen atom
The formula
is
nitrogen atom
4HNO4
hydrogen atom
oxygen atom
Draw molecular
diagrams using
spheres to
represent the
following:
2H2SO3
H is connected to O
S is connected to O
4AsBr5
Some formulas have brackets which are
used to shorten what is written.
For instance instead of writing
CaCaCaPO4PO4
Ca3(PO4)2
Ca
P
O
Ca3(PO4)2
The composition of this compound is
3 parts calcium
2 parts phosphorus
8 parts oxygen
Determine the compositions of each of
the following compounds
Mg3(PO2)2
3 parts magnesium, 2 parts phosphorus,
4 parts oxygen
Fe(C2H3O2)3
1 part iron, 6 parts carbon, 9 parts
hydrogen, 6 parts oxygen
Mn(C2O4)2
1 part manganese, 4 parts carbon, 8 parts
oxygen
Na2Cr2O7 2 parts sodium, 2 parts chromium, 7 parts
oxygen
(NH4)3P2O7
Identify the compositions of the following
CaCO3
1 part calcium, 1 part carbon, 3 parts
oxygen
Mg(ClO3)2
Mg ClO3 ClO3
1 part magnesium, 2 parts chlorine, 6
parts oxygen
Al2(SO4)3
Fe(NO2)6
Al2(SO4)3
2 parts Aluminum
3 parts Sulfur
12 parts Oxygen
Fe(NO2)6
1 part iron
6 parts nitrogen
12 parts oxygen
Cr(NO3)6
Zn(ClO2)2
Ag3(Cr2O7)5
(N3H5P2)4(CaCl3P4)3
(C5H12O21)3(Se3O8)4
Mixtures can have
more than one kind
of molecule. For
these situations
more than one
formula is used.
2SO3, 3SO2
Mixtures can be classified into 2
different groups on the basis of
whether or not they are uniform
throughout (homogeneous) or
whether or not there is more than one
phase (heterogeneous).
Homogeneous mixtures are called
solutions. Heterogeneous mixtures
are called mechanical mixtures.
Physical Properties can be observed
without forming a new substance. They
include colour, form, smell, texture,
quantity, density, boiling point, melting
point, conductivity, elasticity, ductility,
malleability, etc. Quantitative physical
properties are measured (mass, volume).
Qualitative properties are not measured
(colour for instance)