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Chemistry – Year 11

Elements, Compounds and Mixtures

[1
...
Fortunately for
most of us, Chemists have classified all substances into three basic
groups – Elements, Compounds and Mixtures
...
All
substances on the periodic table
are elements
...
This
can be shown by the Separation Line on the Periodic Table, where the
elements on the left of the line are metals and those to the right are nonmetals
...
) However, recently, the elements touching ‘the stairs’ have
been debated to be reclassified as ‘metalloids’, where their properties
show both metallic and non-metallic properties
...
Like Elements, they also have two subsections –
Covalent (non-metallic) and Ionic (metallic) Compounds
...
If a mixture of Iron and
Sulfur is heated intensely, an
Iron + Sulfur  Iron (II) Sulfide
extremely exothermic reaction takes
place, forming a black, non-magnetic solid
...


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Chemistry – Year 11

Mixtures
A Mixture consists of two or more substances which are not chemically
combined, and easily separated by either physical or chemical means
...

An example of a mixture is atmospheric air
...

Using the same mixture of Sulfur and
Iron as earlier, it can be easily separated
into its pure constituent elements
...
Just use a
bar magnet and the iron will be attracted
to it, leaving the sulfur behind
...
This is why several separation
techniques have been developed
...

A substance which is unable to
dissolve in a liquid
...

The liquid which dissolved the
solute
...

The solid which remains after
filtration
...

Liquid which passes through a
condenser
...


Ductility

Liquids which do not mix
completely and form layers
...


Malleability

Ability to be bent into shape
...

separation of a soluble solid
(solute) from the liquid it is
dissolved in (solvent)
...
This
technique is a combination of two
different processes: evaporation
followed by condensation (Liebig
Condenser)
...

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Chemistry – Year 11

Fractional Distillation
The Separation of liquids by simple
distillation is more difficult than a solid
...
This is when fractional distillation is
used
...
Each vapour comes into contact with a surface at a
lower temperature
...
This results in the
insides of the column slowly heating up, letting the substances go further
and further up until the one with the lowest boiling point reaches the top
in gaseous form
...
An example where you would use this method is
when separating a mixture of ethanol (with a boiling point of 78
...

Paper Chromatography
Paper Chromatography is a technique used in the separation of a
mixture of solutes in a solution
...
The separation depends on a difference in the
solubility of the solutes and differences in the degrees of physical
attraction between the solutes and the paper
...


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Chemistry – Year 11

Classification of Metals, Non-Metals, Compounds and Mixtures
All substances can either be classified as a mixture, an ionic or covalent
compounds, non-metal element or metal element
...
5
-78
0
186

Yes
No
Yes
N/A
Yes

Poor
Poor
Poor
Poor
Poor

No
No
No
Low
No

No
No
No
No
No

Var
...

1400 - 1450
Var
...

- Not Ductile or
Malleable
Covalent Compounds:
- Low Melting Point
- Sometimes soluble,
Poor conductor of heat
sound and electricity
- Not Malleable or
Ductile

Mixtures:
All properties depend on
constituent components
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Chemistry – Year 11

High Performance Liquid Chromatography (HPLC)
High Performance Liquid Chromatography is an instrumental analysis
which will separate the mixture into
its component parts
...
The
X Axis shows the retention time whilst
the Y shows the concentration
...

Even though HPLC is very accurate, some chemicals can have the
same retention times
...
Otherwise it can be used to confirm
the results of the HPLC Chromatogram
...
These particles are moving continuously (until they are
cooled to -273
...
This is kinetic theory:
Solid

Gas
- Particles
- Far apart
- Cannot
- High
- Fixed
- Fill whole

close together
...

- Can be slightly compressed
...

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