1. Elements,
Compounds and
Mixtures

2. Elements
Elements are basic substances which
cannot be further broken down into
simpler substances by chemical methods.
115 elements (91 occur naturally, 24
made artificially by scientists)
Classified by properties (ie. metal or
nonmetal)
 Atom - Smallest part of an element that
can exist as a stable entity. Represented
by symbols. (seeTable 2.4 – you must
have these memorized!!!)

3. Takealookatthechartoftheelementnames
andsymbolsthatyouneedtomemorize!
Now….OUTLINE these elements in
BLUE on your periodic chart!

4. Molecules -
small
groups of
joined
atoms
Diatomic
Molecules
 Molecules that are
formed from 2
atoms of a single
element.
 H2, O2, N2, F2, Cl2,
Br2, and I2
 Memorize these!
Highlight these
green on your
periodic chart!!!
Monatomic
Molecules
 These are gaseous
elements that exist as
separate, individual
atoms (they tend not to
bond with themselves
or other elements.)
 He, Ne, Ar, Kr, Xe, Rn
 Memorize these!
Highlight these red on
your periodic chart!

5. Molecules -
small groups
of joined
atoms
Molecules can also be formed between
different types of atoms:
i.e. H20
We call this type of molecule a compound.

6. Compounds
Compounds are pure substances
which are formed when 2 or more
elements chemically combine.
Compounds cannot be separated by
physical means – only by chemical
reactions.
The properties of compounds are
very different than their component
elements.

7. Mixtures
A mixture contains more than one
substance (elements and/or
compounds.)
Mixtures can be physically
separated.
Composition is mixed and properties
are those of the individual elements.

8. Element,
Compound or
Mixture?

9. Element,
Compound or
Mixture?

10. Element,
Compound or
Mixture?

11. Element,
Compound or
Mixture?

12. Separating
Mixtures
If a solid substance is soluble it will
dissolve when added to a liquid and
form a solution. The liquid is called
the solvent and the dissolved solid is
called the solute.
If a solid substance is insoluble it
does not dissolve in liquid.

13. Separating
solid/liquid
mixtures
1. Filtering
2. Decanting
3. Evaporating
4. Crystallizing
5. Centrifuging
6. Simple Distillation

14. Filtering
Pour mixture into a
funnel containing
filter paper.
The residue (solid)
is trapped in the
filter paper while
the filtrate (liquid)
passes through it
into a collection
container below.

15. Decanting
Slowly pour the
mixture into a
collection
container
allowing the
filtrate to run
along a glass rod
to prevent
splashing.

16. Evaporating
Evaporation is good if
a solid has been
dissolved in a solvent
and can’t be filtered or
decanted.
Slowly heat the
mixture until the
solvent has been
completely evaporated
and leaves the solid
behind.

17. Crystallizing
This is a process that uses the sun to
evaporate salt from brine. Brine is a
supersaturated solution which contains
as much salt as it can dissolve. When the
water is evaporated the salt crystallizes.

18. Centrifuging
We use centrifuging when the solid
particles are so small they don’t settle to
the bottom of a solution, but remained
dispersed in suspension. Centrifuging
involves spinning the suspension very fast
so that the solid is flung to the bottom of
the tube. This can be used to separate blood
cells from blood plasma.

19. Simple
Distillation

20. Simple
Distillation
The solution is heated in the flask
until it boils. The steam rises into
the Liebig condenser where it
condenses back into a liquid and
collects in the beaker. The solute is
left behind in the flask. This is one
way to remove dissolved salt from
water.

21. Separating
liquid/liquid
mixtures 1. Separating Funnel
2. Fractional
Distillation

22. Separating
Funnel
A separating
funnel is used to
separate liquids
that are
immiscible
(liquids that
don’t mix). The
lower layer can
be released by
opening the tap.

23. Fractional
Distillation

24. Fractional
Distillation
Fractional Distillation is used to separate
liquids that are miscible (mixable). It relies
on the fact that the miscible liquids have
different boiling points. This is one way to
separate ethanol and water. Ethanol boils at
78˚C while water boils at 100˚C. As the
mixture is heated the vapor is mostly
ethanol and some water. The water vapor is
condensed out of the vapor and returned to
the flask in the fractionating column which
has many beads in it.

25. Fractional
Distillation

26. Separating
solid/solid
mixtures 1. Chromatography
2. Solvent extraction

27. Chromatography

28. Chromatography
Chromatography is used to separate two
or more solids such as inks or dyes. A
spot of ink is placed on chromatography
paper. The paper is placed in solvent. As
the solvent moves up the paper the dyes
are carried with it. They separate
because they are dissolved at different
rates by the solvent and absorbed to
different degrees by the
chromatography paper. An Rf value can
be calculated. It is the ratio of the
distance travelled by the solute (solid) to
the distance travelled by the solvent.

29. Chromatography

30. Solvent
Extraction
Solvent extraction can be
used to separate two
solids. For example, we
can use water to dissolve
sugar (solid 1) from
crushed sugar cane (solid
2). The sugar can then be
separated from water by
evaporation.

31. Discuss
with a
partner:
If I gave you a mixture
of water, oil, salt, sand
and iron chips how
would you separate
them?