UNIT 2 – MATTER AND ITS PROPERTIES
INDEX
1. What is matter
2. States of matter
Macroscopic approach
Microscopic approach, kinetic theory
Changes of state
3. Properties of matter
General properties
Mass, volume, temperature....
Characteristic properties
Density
Boiling point
Melting point
4. The gaseous state
Boyle’s law
Charles’ law
Gay –Lussac’s law
29
UNIT 2 – MATTER AND ITS PROPERTIES
1.WHAT IS MATTER?
Matter is everything that has mass, occupies a volume and has
properties that can be measured.
2.STATES OF MATTER
Macroscopic approach:
SOLIDS:
•
•
•
They have a fixed volume ( they can´t be compressed)
They have a fixed shape
They can´t flow
LIQUIDS
•
•
•
They have a fixed volume (they can be slightly compressed)
They take the shape of the container
They can flow
GASES
•
•
They fill the whole container. They have an indefinite volume.(they
can be compressed)
They take the shape of the container. They have an indefinite shape
30
UNIT 2 – MATTER AND ITS PROPERTIES
Microscopic approach: Kinetic matter theory:
SOLIDS:
•
•
•
Particles of solids are tightly packed in a regular pattern.
Particles vibrate around a fixed position.
Particles are strongly attracted to each other.
LIQUIDS
•
•
•
Particles of solids are randomly packed (In a mess)
Particles can move around.
Particles are attracted to each other.
GASES
•
•
•
Particles of gases don´t touch each other
Particles can move around fast in all directions
The forces of attraction are very weak.
Microscopic Explanation of Properties of Solids



Solids have a definite shape and a definite volume because the
particles are locked into place
Solids are not easily compressible because there is little free space
between particles.
Solids do not flow because the particles cannot move and the forces
between them are very strong.
31
UNIT 2 – MATTER AND ITS PROPERTIES
Microscopic Explanation of Properties of Liquids



Liquids have an indefinite shape because the particles can slide past
one another.
Liquids are not easily compressible and have a definite volume
because there is little free space among the particles.
Liquids flow easily because the particles can move and the forces
between them are not so strong.
Microscopic Explanation of Properties of Gases



Gases have an indefinite shape and an indefinite volume because the
particles can move past one another.
Gases are easily compressible because there is a great deal of free
space between particles.
Gases flow very easily because the particles randomly move and the
forces between them are very weak.
Changes of state
The names for the changes are:
The change from liquid to solid is solidifying (in the case of water is
freezing)
The change from solid to gas is sublimation
The change from gas to solid is deposition
Language:
The names of some changes end in –ing: melting, boiling, condensing,
freezing, solidifying.
But we say sublimation and deposition!
When we are speaking about a substance (for example water) we say :
32
UNIT 2 – MATTER AND ITS PROPERTIES
It melts, it boils, it freezes, it condenses, it solidifies, it sublimates.
When a liquid becomes a gas (in general we call it vaporisation), it can
happen in two ways:
Evaporation:
 It happens when only the particles on the surface of the liquid
become a gas.
 It happens at any temperature.
Boiling:
 It happens when particles throughout the liquid become bubbles of
gas and rise to the surface and escape from the liquid.
 It happens at a certain temperature for each liquid.
When water is in the gaseous state we call it steam.
33
UNIT 2 – MATTER AND ITS PROPERTIES
3.PROPERTIES OF MATTER
We can classify the properties in two groups:
General properties
Characteristic properties
General properties:
 They are physical features that describe matter but can change
without changing the substance.
Examples: size, shape, texture, temperature, state, volume.
Characteristic properties:
 They are fixed properties that do NOT change, they have always the
same value for the same substance
Examples: boiling point, melting point, solubility, conductivity,
hardness ,pH, flammability, density.
In this unit we are going to study:
Density
Boiling point
Melting point
As characteristic properties are not affected by physical changes, they
can be used to identify matter
DENSITY
Density = amount of matter per volume unit.
D = m/v (g/cm3)
• Mass is usually expressed in grams
• Volume is usually expressed in cm3 or liters, etc.
So the units can be:
g/ml
g/ cm3
Kg/l
Kg/m3
34
UNIT 2 – MATTER AND ITS PROPERTIES
MELTING POINT
It is the temperature at which a solid becomes a liquid.
It always happens at the same temperature.
It is also the temperature at what a liquid becomes a solid.(freezing)
BOLILING POINT
It is the temperature at which a liquid becomes a gas.
It happens always at the same temperature.
It is also the temperature at which a gas becomes a liquid.(condensing)
35
UNIT 2 – MATTER AND ITS PROPERTIES
Language:
Here you have several verbs that you can use to describe the curves:
To turn into
To increase
To rise
Rise X raise
The sun rises.
Please raise your hand
Each substance has a certain melting point and a certain boiling point:
36
UNIT 2 – MATTER AND ITS PROPERTIES
4.THE GASEOUS STATE
The kinetic matter theory explains that:
A gas is composed of small particles.
The particles have an insignificant volume and are far apart from one
another.
There is empty space between particles.
Little attractive forces between particles.
The particles in a gas move in constant random motion.
Particles path is only changed by colliding with another particle or
the sides of its container.
Gases have several properties:
They exert pressure:
Gas particles exert pressure by colliding with objects in their path.
The sum of all of the collisions makes up the pressure the gas
exerts.
There are several units for measuring pressure :
Atmospheres (atm)
Millimeters of Mercury (mmHg)
Gases occupy volume:
The volume of the gas is simply the volume of the container it is
contained in.
The metric unit of volume is the cubic metre (m3)
Gases have temperature:
The temperature of a gas is generally measured with a thermometer
in Celsius.
All calculations involving gases should be made after converting Celsius to
Kelvin temperature.
Kelvin = C° + 273
37
UNIT 2 – MATTER AND ITS PROPERTIES
GASES LAWS
Studies of the behavior of gases have become mathematical laws
which we can use to predict quantitative outcomes.
https://www.youtube.com/watch?v=Osq71Y82uac ( Hasta 3.52 min)
BOYLE´S LAW
https://www.youtube.com/watch?v=Xto88gMmDzw (Hasta 4,28)
Robert Boyle observed the relationship between pressure and volume
of a gas.
During his experiments, temperature and the amount of gas weren’t
allowed to change
Boyle’s Mathematical Law: PV = k
What if we had a change in conditions?
since PV = k
At constant temperature the volume of a gas is inversely roportional
to the pressure.
As volume increases, pressure decreases.
38
UNIT 2 – MATTER AND ITS PROPERTIES
CHARLES’S LAW
https://www.youtube.com/watch?v=7ZpuMBkf1Ss (hasta 4.51)
Jacques Charles determined the relationship between temperature
and volume of a gas.
During his experiments, pressure of the system and amount of gas
were held constant.
Charles’s Mathematical Law: V/T = k
What if we had a change in conditions?
since V/T = k
At constant pressure the temperature of a gas is directly proportional to
the volume.
As temperature increases, volume increases.
39
UNIT 2 – MATTER AND ITS PROPERTIES
GAY-LUSSAC´S LAW
https://www.youtube.com/watch?annotation_id=annotation_3630315551&f
eature=iv&index=16&list=PLi01XoE8jYoi5fLBY64f6ZUuktgTFb2H3&src_vid
=Xto88gMmDzw&v=0Oq7bCSDPxE (hasta 4,46)
Lussac determined the relationship between temperature and
pressure of a gas.
During his experiments volume of the system and amount of gas were
held constant.
The pressure increases when temperature increases because the
molecules are moving faster and colliding against the sides of their
containers more often.
Therefore, the pressure inside that container is greater, because
there are more collisions.
Lussac’s Mathematical Law: P/T = k
40
UNIT 2 – MATTER AND ITS PROPERTIES
What if we had a change in conditions?
since P/T = k
At constant volume the temperature of a gas is directly proportional to the
pressure.
As temperature increases, pressure increases.
UNIT 2 - MATTER AND ITS PROPERTIES.
Activities
A1-States of matter. ( listening activity)
You are going to listen to a text and you have to fill the bubbles of the
“mind map”.
41
UNIT 2 – MATTER AND ITS PROPERTIES
42
UNIT 2 – MATTER AND ITS PROPERTIES
A2-States of matter (speaking activity)
Help yourself with this chart:
Key words (one or two in each
cell)
How are they packed?
How do they move?
How are them attracted to
each other?
Now, without any help say sentences about particles and your
partner has to guess which state you are speaking about:
A3-Evaporation and boiling
43
UNIT 2 – MATTER AND ITS PROPERTIES
A4-Changes of state (writing and speaking activity)
A5-Density
44
UNIT 2 – MATTER AND ITS PROPERTIES
A6-Density
A7-Density
45
UNIT 2 – MATTER AND ITS PROPERTIES
A8-Density (writing and speaking activity)
A9-Density
46
UNIT 2 – MATTER AND ITS PROPERTIES
A10-Changes of state
47
UNIT 2 – MATTER AND ITS PROPERTIES
A11-Pressure
A12-Gases Laws (Language activity)
A13-Gases laws (Language activity)
48
UNIT 2 – MATTER AND ITS PROPERTIES
A14-Gases laws
1 litre of a gas at standard temperature (T=cte) and
pressure is compressed to 473 mL. What is the new
pressure of the gas?
A man heats a balloon in the oven. If the balloon initially
has a volume of 0.4 liters and a temperature of 20 0C, what
will the volume of the balloon be after he heats it to a
temperature of 250 0C?
If I initially have a gas at a pressure of 12 atm, a volume of
23 liters, and a temperature of 200 K, and then I raise the
pressure to 14 atm and increase the temperature to 300 K,
what is the new volume of the gas?
49
UNIT 2 – MATTER AND ITS PROPERTIES
UNIT 2-MATTER AND ITS PROPERTIES
EXERCISES
1
2
50
UNIT 2 – MATTER AND ITS PROPERTIES
3
4
5
What is the density of a piece of wood that has a mass of 25.0 grams and a volume of 29.4 cm3?
6
A piece of wood that measures 3.0 cm by 6.0 cm by 4.0 cm has a mass of 80.0 grams. What is the
density of the wood? Would the piece of wood float in water? (volume = L x W x H)
51
UNIT 2 – MATTER AND ITS PROPERTIES
7
A cup of gold colored metal beads was measured to have a mass 425 grams. By water displacement,
the volume of the beads was calculated to be 48.0 cm3. Given the following densities, identify the
metal.
Gold: 19.3 g/mL
Copper: 8.86 g/mL
Bronze: 9.87 g/mL
8
I threw a plastic ball in the pool for my dog to fetch. The mass of the ball was 125
grams. What should be the volume to have a density of 0.500 g/mL.?
9
The density of aluminium is 2.70 g/mL. If the mass of a piece of aluminium is 0,244 Kg,
what is the volume of the aluminium?
10
52
UNIT 2 – MATTER AND ITS PROPERTIES
11
12
13
53
UNIT 2 – MATTER AND ITS PROPERTIES
14
15
54
UNIT 2 – MATTER AND ITS PROPERTIES
16
Write in right order the particle diagrams
0
17 If I initially have a gas with a pressure of 84 kPa and a temperature of 35 C and I heat
it an additional 230 degrees, what will the new pressure be? Assume the
volume of the container is constant.
of 2600 liters. If the sun heats my car from a
18 My car has an internal volume
0
0
temperature of 20 C to a temperature of 55 C, what will the pressure inside my
car be? Assume the pressure was initially 760 mm Hg.
55
UNIT 2 – MATTER AND ITS PROPERTIES
56
UNIT 2 – MATTER AND ITS PROPERTIES
LABORATORY - COOLING CURVE.
Work in groups of three people.
You are going to read the following instructions. First, cut the pictures
bellow with the scissors. Then, follow the instructions moving the pictures
and doing exactly what you are asked to do.
Finally show the teacher how you did it. Ask any questions you are
interested in, before carrying out the experiment.
Instructions:
Put the gauze on the top of the gas heater.
Put a beaker over the gauze and fill it with water.
Put 5 grams of naphthalene into a Pyrex test tube.
Add a thermometre to the test tube.
Insert the test tube in a 500 ml beaker of water.
Stick the test tube to a stand with a clamp in order to put it vertically and
inside the water, without touching the beaker.
Light the gas heater.
Heat the naphtalene until it melts
Switch off the heater and remove the heater from the water bath.
Record the temperature of the naphtalene every 15 seconds while it is
cooling. Remember to stir the naphtalene with the thermometre gently.
Stop measuring the temperature when it gets to 70 degrees.
Draw the cooling curve representing the temperature/time data.
57
UNIT 2 – MATTER AND ITS PROPERTIES
58
UNIT 2 – MATTER AND ITS PROPERTIES
59
UNIT 2 – MATTER AND ITS PROPERTIES
60
UNIT 2 – MATTER AND ITS PROPERTIES
GLOSSARY
boiling [ˈbɔɪlɪŋ]
characteristic [ˌkærɪktəˈrɪstɪk]
curve [k3ːv]
evaporation [ɪˌvæpəˈreɪʃən]
flow [fləʊ]
indefinite [ɪnˈdefɪnɪt]
liquid [ˈlɪkwɪd]
matter [ˈmætər]
naphthalene [ˈnæfθəliːn]
particle [ˈpɑːtɪkl]
pressure [ˈpreʃər]
raise [reɪz]
rise [raɪz]
solidify [səˈlɪdɪfaɪ]
sublimation [ˌsʌblɪˈmeɪʃən]
vaporization [ˌveɪpərəɪˈzeɪʃən]
volume [ˈvɒljuːm]
61