1. MATTER
1.- Introduction.
Matter is all what we see, smell or touch. It can be hard as iron, fragile
as glass, viscous as oil...
In this unit we will study matter, some of its properties and changes the
heat produces in its state, and even on its composition.
Also we learn about the difference between physical changes and
chemical changes of matter and some chemical changes that happen in
living organisms.
2.- Matter.
The universe is composed of matter: stars, planets, mountains, rocks,
sand, clouds, etc. But, in the universe, there are things that they are not
matter: the light, sound, heat, electricity...
What are the differences between the previous substances ? First we
must to define what is matter:
Matter is everything that has mass and that occupies a space.
3.- General and specific properties.
Matter has many properties: strength, temperature, flexibility,
brightness, mass, volume, transparency, solubility, etc. However, not all
them we will serve to differentiate between some bodies.
The properties of matter can be classified in:
I. General properties. Those are not used to distinguish what type of
substance it is. They are mass, volume and temperature.
II. Specific properties. They are depend on the kind of substance that is
made. Serves to differentiate a substance of another. They are odor,
solubility, density.
Two different material systems cannot have the same specific
properties.
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2. 4.- The states of matter.
The main states of matter are solid, liquid and gas. The state in which
we find matter depends on the temperatura and pressure. A piece of iron
or a stone are matter in solid state. Water and oil are matter in liquid
state. Nitrogen and oxygen are matter in gaseous state. In each state,
matter has different properties.
 Solids have constant volume and shape. Their shape and volume don´t
change when we put them in a different container. Their particles
are not compressed because they are together and strongly united.
The particles only present vibration movement
 Liquids have a constant volume but not shape of their own. If we pass a
litre of water from a bottle to a pitcher, the water takes the form of
the pitcher but its volume doesn´t change. Their particles almost are
not compressed and they are at a fixed distance and movement.
The particles can slip some over others.
 Gases change volume and shape. Gases compress easily because their
particles are widely separated and move freely. When you click a
balloon, air escapes and extends across the room. It passed to the
form and the volume of the room.
Solid Liquid
Gas
Both liquids and gases are fluid. They can pass through a hole in a solid
and can be driven tubes.
We can summarize the matter states and its properties in the following
table:
SOLIDS LIQUIDS GASES
Have their own form. Don´t have their own form. Don´t have their own form.
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3. Have constant volume. Have constant volumen. Don´t have constant volumen.
Don´t compress. They have difficulty compress. They compress easily.
Don´t flow. They flow. They flow.
5.- Changes of state.
When matter changes from one state to another, there is what is
known as a change of state. These changes of state can happen when
bodies change their temperature or pressure. There are some changes of
state:
 Melting is when a solid turns into a liquid. For example, if ice is
heated, it changes to water.
 Solidification is the reverse transformation, when a liquid turns into a
solid. For example, if water is cooled, it changes to ice.
 Vaporization is when a liquid turns into a gas. There is two forms:
• Boiling.- If the transformation happens a fixed temperature and
quickly. When heat water comes a time in which begins to boil.
There are big gas bubbles and vaporization occurs in
everywhere of the water. This temperature is called boiling
temperature. The boiling temperature of water is 100 ºC.
• Evaporation. It occurs at a lower temperature and is slower.
For example, a pond water evaporates gradually until it dries,
the clothes tend to dry out….
 Condensation is the transformation of a gas into a liquid. For example, if
water vapour is cooled, it changes to water. The classroom filled
with steam in winter.
 Sublimation is when a solid turns into a gas without passing through
the liquid state. The reverse process, when a gas turns into a solid
without passing through a liquid state, is inverse sublimation or
deposition. For example, the naphthalene and iodine go directly from
solid to a gas state.
Matter can exist in three states: solid, liquid and gaseous. When matter changes from
one state to another, it undergoes a change of state.
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4. Liquid water Solid water
Water vapour
State changes occur by heating or cooling bodies. For example, the water
becomes ice if cooled in the freezer and butter becomes liquid when
heated in the oven.
The following chart summarizes changes of state:
Sublimation
Melting Vaporisation
SOLID LIQUID GAS
S
Solidification
Condensation
Regressive Sublimation
6.- Physical and Chemical changes.
Matter can undergo two types of change:
 Physical changes.- They are those in which the substances of bodies
don´t change. For example, when a glass bottle breaks into small
bits, each of the bits is still glass. These are examples of physical
change: changes of state, movement, fragmentation, dilation…..
Physical changes may be of two types: reversible and
irreversible:
• Reversible changes occur when the matter can recover its initial
appearance. Stretching a rubber, for example, its length
increases, and if we stretch it, retrieves its original form.
The same applies to the cloth flags.
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5. • Irreversible changes occur when it is impossible to matter to
recover its initial state. For example, if we make the wood
sawdust
Wood
Sawdust
A physical change is a change in a property of matter without change its
composition.
 Chemical changes.- Are those which produce a change in the
composition of matter, producing new substances with different
properties to that we had at the beginning. Combustion (when
wood burns, turn on a match..), fry an egg, make bread, digesti
food and fermentation (sugar turns into alcohol) are examples of
chemical changes.
A chemical change produce changes in the properties of the substances into
different ones.
ACTIVITIES
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6. 1.- Looking for the meaning of the words in the dictionary:
a. Viscosity.
b. Malleable.
c. Fragile.
d. Density.
e. Opaque.
f. Conductor.
g. Waterproof.
h. Transparent.
i. Translucent.
j. Strong.
2- Write the names of solids with these features:
a) One hard and other soft.
b) One very fragile and one that is not.
c) Two very waterproof solids.
d) One more dense than water.
e) One less dense than water.
3.- Order from highest to lowest viscosity these fluids: honey, oil and
water.
4.- Complete the box using the following properties: mass, temperature,
color, solubility, density, volume, viscosity.
MATTER PROPERTIES
General Specific
5-Completes the following examples of specific properties using the
following words: boats, blankets, windows.
a) Transparency and the hardness of the glass take advantage to
build................
b) Wool is a good thermal insulator, and is used to make......................
c) The fact that wood is waterproof and has lower density that water
favouring use to build........................
6.- What are the specific properties of the previous exercise?
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7. 7.- What phrases are general properties and what phrases are specifics
properties?
a) It has a mass of 10 grams.
b) It is shining.
c) It is yellow.
d) Its density is of 19,3 kg/L.
8.- Classifies the following list of substances according to the state in
which they are: glass, wood, water, ice, oxygen, oil, blood, hydrogen,
steel, gold and resin.
SOLID LIQUID GAS
______________________ ______________________ ______________________
______________________ ______________________ ______________________
______________________ ______________________
______________________ ______________________
______________________
9- Indicates several substances in your body that:
a) ... are solid state _____________________________
b) ... are liquid state _____________________________
c) ... are gas state _____________________________
10.- Write constant or variable.
a) Solids have ...................... volume and ..................... form.
b) Liquids have ......................... volume and ......................... form.
c) Gases have ………................. volume and ........................ forma.
11.- Complete the following table:
State Volume Form Compress Flow
Solid
Liquid
Gas
12.- Indicate if the following phrases are physical or chemical changes:
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8. • Melting ice. •
Evaporation a puddle of
• Fermentation of the wine. water.
• Combustion of butane in the • Oxidation of an iron bar.
kitchen. • Dilation of a road train.
• Dissolve some sugar in a • The solidification of the
glass of water. water.
• The photosynthesis.
13.- Indicate which the following physical changes are reversible or
irreversible:
a) To break a paper.
b) To freeze eater..
c) To melt the chocolate..
d) To dissolve an aspirin in water.
14.- Indicates in what cases a chemical change occurs:
a) We break a piece of cloth in pieces.
b) We melt sugar for candy.
c) We freeze water.
d) We do react vinegar with bicarbonate and occurs much gas.
15.- What´s the difference between a physical and chemical exchange?
16.- Copy and complete the following diagram:
Matter
can be in three
can undergo
states
changes
Physic Chemic
can
be as
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9. © Manuel Blanco 2010
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