This document defines and describes different types of mixtures. It explains that a mixture is a combination of two or more substances that are not chemically bonded and do not undergo chemical reactions. Mixtures can be either heterogeneous or homogeneous. Heterogeneous mixtures like soil or cereal in milk are non-uniform, with distinguishable components. Homogeneous mixtures like salt water solutions are uniform throughout with components spread evenly and not visually distinguishable from one another. Common examples of homogeneous and heterogeneous mixtures are provided.
2. What is Mixture?
• Mixture
• A mixture is a combination of two or more
substances, where these substances are
not bonded (or joined) to each other and
no chemical reaction occurs between the
substances.
3. In a mixture, the substances that
make up the mixture:
• are not in a fixed ratio
• keep their physical properties
• can be separated by mechanical means
5. Heterogeneous Mixtures
• A heterogeneous mixture does not have a
definite composition. Cereal in milk is an
example of a heterogeneous mixture. Soil
is another example. Soil has pebbles,
plant matter and sand in it. Although you
may add one substance to the other, they
will stay separate in the mixture. We say
that these heterogeneous mixtures are
non-uniform, in other words they are not
exactly the same throughout.
7. Homogeneous mixtures
A homogeneous mixture has a
definite composition, and
specific properties. In a
homogeneous mixture, the
different parts cannot be seen. A
solution of salt dissolved in
water is an example of a
homogeneous mixture.
8. • When the salt dissolves, it spreads
evenly through the water so that all
parts of the solution are the same,
and you can no longer see the salt as
being separate from the water.
• Think also of coffee without milk. The
air we breathe is another example of
a homogeneous mixture since it is
made up of different gases which are
in a constant ratio, and which can't
be visually distinguished from each
other (i.e. you can't see the different
components).
9. Activity: Substances that Dissolve in Water
Materials:
10 small bottles with cover fruit jelly
salt peanut butter
fine sand alcohol
iron filings cooking
oil
baking soda kerosene
tea leaves extract
10. Write your predictions
• The substances that will dissolve in water
are_______________________________
11. • Half- fill the 7 bottles with water
• Place small amounts of each substance
• half-fill another bottle with water
• mark the level of water in the bottle
• pour alcohol (half the amount of water) in
the same bottle
• Predict if there is a change in the liquid
level
• half-fill another bottle with water
• mark the level of water in the bottle
12. • Pour 2 spoonfuls of oil into the bottle.
Cover and shake.
• what do you think will happen?
• Half fill another bottle with water . Mark the
label of water
• Add kerosene (half the amount of water)
into the bottle
• cover and shake
• what do you think will happen
13. Write your observations on the reaction of the
following substances when placed in water:
SALT_____________________________
SAND:____________________________
IRON FILINGS _____________________
BAKING SODA______________________
TEA LEAVES EXTRACT______________
FRUIT JELLY_________________________
PEANUT BUTTER_____________________
ALCOHOL____________________________
14. • COOKING OIL______________________
• KEROSENE_______________________
• the subtances that dissolved in water
were____________________________
• CONCLUSIONS______________________
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