domingo, 26 de abril de 2015
domingo, 12 de abril de 2015
UNIT 6: MATTER
UNIT 6: MATTER
INDEX:
1. MATTER
1.1.-Properties of matter
1.2.-States of matter
2.- MATTER CHANGES
2.1.- Physical changes
2.2.- Chemical changes
3.- PURE AND MIXED SUBSTANCES
1.- MATTER ___________________________________________________________________
Ø Matter
is everything that forms the universe and that occupies space.
1.1.- PROPERTIES OF MATTER
Matter has
both general and specific properties.
Ø General properties are common to all types of matter.
They are:
·
Mass. It is the amount of matter in an object. Mass
is measured in grams or kilograms.
Ø Specific properties permit us to differenciate between
different types of matter. They are:
·
Density. It is the relantioship between an object´s
mass and volume.
·
Hardness.
-
Matter
is resistant when it is difficult to scratch or cut.
-
Matter
is fragile when it is easy to break.
·
Elasticity.
-
Matter
is elasctic when it returns to its original shape after stretching or
bending it.
·
Water resistant.
-
Matter
is waterproof when liquids cannot go throught it.
·
Transparency
-
Matter
is transparent when light can pass throught it.
1.2.- STATES OF MATTER.
Matter exists in three states:
Ø Solid.
-
It
has its own shape.
-
It
has the same volume.
Ø Liquid.
-
It
does not have its own shape. It adapts the shape to the container it is in.
-
It
always keeps the same volume
Ø Gas.
-
It
does not have its own shape.
ACTIVITIES
1.- Complete the sentences in your notebook
- The main properties of matter are: __________________
and __________________ .
- The characteristic properties of matter lets us ____________ them.
- The states of matter are: ________________ , ________________ and
_________________ .
2.- Write the properties to their examples:
Density , Hardness , Elasticity,
Transparency and water resistant.
- A window lets sunlight
in. ___________________
- Bending a
rubber toy. _____________________
- A raincoat protect us
from the rain. ___________
- Oil
floats on water _________________
- Dropping a glass on the floor.
________________
Ø Matter changes constantly and does
not always stay the same. There are two types of changes: physical and chemical
changes.
2.1.- PHYSICAL CHANGES
Ø The composition of matter does not
change, although its appearance, size and temperature are different.
Ø There are two types of physical
changes:
·
Irreversible: the matter cannot go back to its
original state.
·
Reversible: The matter can go back to its
original state.
Ø Heat produces other reversible changes
in the state:
·
Fusion: A solid becomes a liquid.
·
Evaporation: A liquid becomes a gas.
·
Boiling: An entire liquid reaches a certain
temperature and becomes a gas.
·
Condensation: A gas becomes a liquid.
·
Solidification: A liquid becomes a solid
2.2.- CHEMICAL CHANGES
Ø The composition and properties of
matter change during chemical changes, but its mass does not.
For example, the composition and properties of wood change when it
burns, but its mass is the same as the sum of the mass of its ashes and smoke.
Ø There are three types of chemical
changes:
·
Oxidation occurs when the oxygen in the air
mixes with certain substances. For example, water and oxygen cause oxidation.
·
Combustion occurs when a material mixes with
oxygen and it burns. It is a fast oxidation that releases light and heat. Materials
like wood, paper or gasoline are combustible because they can burn. For
example: Burning a sheet of paper.
·
Fermentation occurs when there is no oxygen and
certain living things, like yeasts or some bacteria, help create the chemical
change of fermentation. There are two types of fermentation:
-
Natural:
when food spoils
-
Artificial:
when human makes changes for industrial purposes, like making yoghurt, wine or
bread.
3.- PURE AND MIXED SUBSTANCES _____________________________________________
Ø Pure substances cannot be physically
separated into other substances.
Ø Mixtures are made up of two or more
pure substances that can be physically separated. There are two types of
mixtures:
·
Heterogeneous
·
Homogeneous
Ø In heterogeneous mixtures, we can separate
substances in different ways:
·
Filtration: we can separate a solid and a liquid.
For example, sand and water.
·
Decantation: We can separate two liquids of
different densities. For example, oil and water.
Ø In homogeneous mixtures, we
can separate substances in different ways:
·
Evaporation: we can separate a solid and a
liquid. For example, salt and water.
·
Distillation: We use heat to separate different
liquids.
ACTIVITIES
1.- Complete the chart.
Separating
|
Heterogeneous mixtures
|
Homogeneous mixtures
|
A solid and a liquid
|
|
|
Two liquids
|
|
|
2.- Correct the sentences.
·
Matter
always stay the same.
·
The
composition of matter always changes when its appearance changes.
·
A
chemical change is when matter changes into something different but doesn´t
create a new substance.
·
Physical
changes are irreversible when matter can go back to its original state.
·
The
changes of state of matter are irreversible.
3.- What´s the difference between pure and mixed
substances?
4.- Complete the sentences:
·
In
chemical changes, matter can change its ______________ and its ___________, but
not its _________ .
·
____________
, ______________ and ______________are chemical changes.
·
Oxidation
occurs when a substance mixes with the oxygen in the _________ and makes a
____________ substance.
·
Combustion
is a very _______________ oxidation where a material mixes with oxygen and
__________. It releases __________ and __________.
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