MATTER AND TEMPERATURE Chapter Ten: Matter and Temperature 10.1 The Nature of Matter 10.2 Temperature 10.3 The Phases of Matter.
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Transcript MATTER AND TEMPERATURE Chapter Ten: Matter and Temperature 10.1 The Nature of Matter 10.2 Temperature 10.3 The Phases of Matter.
MATTER AND TEMPERATURE
Chapter Ten: Matter and
Temperature
10.1 The Nature of Matter
10.2 Temperature
10.3 The Phases of Matter
Chapter 10.1 Learning Goals
Define matter.
Identify the atom as the building
block of matter.
Explain the basis for classifying
matter as either pure substances or
mixtures.
Investigation 10A
Pure Substance or Mixture
Key Question:
Is the matter a pure substance or is it a
mixture?
10.1 The Nature of Matter
Matter is a term used to describe anything
that has mass and takes up space.
Greek philosophers Democritus and
Leucippus proposed that matter is made
of tiny particles called atoms.
Atoms were an idea that few believed.
The first evidence was called Brownian
motion for Robert Brown, who first noticed
the jerky motion of tiny particles.
10.1 The Nature of Matter
Throwingthe
marbles
Varying
at a tire
tube
mass
and
size
moves
the tube
of
particles
that
smoothly.
collide can have
different
Throwing the
same marbles at a
effects.
foam cup moves
the cup in a jerky
way, like
Brownian motion.
10.1 Elements
An element is a pure
substance that cannot be
broken down into other
substance by chemical or
physical means.
All of the matter you are
ever likely to experience
is made from one or more
elements in nature.
10.1 Elements
For example, water
can be broken down
into its elements,
hydrogen and oxygen,
when energy is added.
10.1 Atoms
A single atom is the smallest particle
that retains the chemical identity of
the element.
10.1 Atoms
Carbon atoms are different from
sodium, aluminum, or oxygen atoms.
They have different masses.
10.1 Compounds and elements
Compounds are two or more
different elements chemically
bonded together.
10.1 Examples of compounds
Compounds
contain more
than one type
of atom joined
together.
10.1 Molecules
A molecule is a group of two or
more atoms joined together
chemically.
10.1 Mixtures
How
are
Howmany
manyatoms
molecules
inare
this
in mixture?
this mixture?
Many substances
you encounter are
a mixture of
different elements
and compounds.
10.1 Elements, compounds, and
mixtures
Can you distinguish between atoms and
molecules in these images?
Chapter Ten: Matter and
Temperature
10.1 The Nature of Matter
10.2 Temperature
10.3 The Phases of Matter
Chapter 10.2 Learning Goals
Define temperature in terms of
the motion of atoms and
molecules.
Convert among Fahrenheit,
Celsius, and Kelvin scales.
Describe the relationship between
thermal energy and temperature.
10.2 Temperature
There are two common
temperature scales.
On the Fahrenheit
scale, water freezes at
32 degrees and boils at
212 degrees.
The Celsius scale
divides the interval
between the freezing
and boiling points of
water into 100 degrees.
Solving Problems
A friend in Paris sends you a recipe for a
cake. The French recipe says to bake the
cake at a temperature of 200 °C for 45
minutes.
At what temperature should you set your
oven, which uses the Fahrenheit scale?
Solving Problems
1. Looking for:
…temperature in degrees Fahrenheit
2. Given:
…temperature 200 C
3. Relationships:
TF = 9/5 TC + 32
4. Solution
TF = (9/5)(200 °C) + 32 = 392 °F
10.2 What temperature really is
Atoms are in constant
motion, even in a solid
object.
The back-and-forth
jiggling of atoms is
caused by thermal
energy, which is a
kind of kinetic energy.
10.2 What temperature really is
Temperature measures the kinetic
energy per molecule due to random
motion.
10.2 Thermometers
A thermometer is an instrument
that measures the exact
temperature.
Most thermometers contain
either a silvery fluid (mercury)
or a red fluid, which is alcohol
containing a small amount of
red dye.
10.2 How a thermometer works
The volume of alcohol in a
thermometer contains huge
numbers of alcohol
molecules.
As temperature increases,
the alcohol molecules move
faster and bounce off each
other.
The liquid alcohol expands
and takes up more space in
the thermometer.
10.2 Measuring temperature
A thermistor is a device
that changes its electrical
resistance as the
temperature changes.
Some digital thermometers
sense temperature by
measuring the resistance
of electrons passing
through wire.
10.2 Liquid-crystal thermometers
Some thermometers contain liquid crystals that
change color based on temperature.
As temperature increases, the molecules of the
liquid crystal bump into each other more and
more.
This causes a change in the structure of the
crystals, which in turn affects their color.
10.2 Absolute zero
Absolute zero is -273°C.
You cannot have a temperature lower
than absolute zero.
Think of absolute zero as the
temperature at which atoms are
“frozen.”
10.2 Converting to Kelvin
The Kelvin
temperature scale
is useful in science
because it starts at
absolute zero.
To convert from
Celsius to Kelvin,
you add 273 to the
temperature in
Celsius.
Chapter Ten: Matter and
Temperature
10.1 The Nature of Matter
10.2 Temperature
10.3 The Phases of Matter
Chapter 10.3 Learning Goals
Identify the phases of matter.
Describe the behavior of atoms
and molecules as matter
undergoes phase changes.
Describe properties of plasmas.
Investigation 10B
Heating and Cooling Curve of
Cetyl Alcohol
Key Question:
What is the
freezing/melting
point of cetyl
alcohol?
10.3 Phases of Matter
On Earth, pure
substances are
usually found as
solids, liquids, or
gases.
These are called
phases of matter.
10.3 The phases of matter
A solid holds its
shape and does not
flow.
The molecules in a
solid vibrate in place,
but on average, don’t
move far from their
places.
10.3 The phases of matter
A liquid holds its
volume, but does
not hold its
shape—it flows.
Liquids flow
because the
molecules can
move around.
10.3 The phases of matter
A gas flows like a liquid,
but can also expand or
contract to fill a
container.
A gas does not hold its
volume.
The molecules in a gas
have enough energy to
completely break away
from each other.
10.3 The phases of matter
When they are close together,
molecules are attracted through
intermolecular forces.
10.3 The phases of matter
The forces in chemical bonds are
stronger than intermolecular
forces.
10.3 Intermolecular forces
10.3 Intermolecular forces
Within all matter, there is a constant
competition between temperature and
intermolecular forces.
When temperature wins the
competition, molecules fly apart and
you have a gas.
When intermolecular forces win the
competition, molecules clump tightly
together and you have a solid.
10.3 Melting and boiling
The melting point is the
temperature at which a substance
changes from a solid to a liquid.
10.3 Melting and boiling
The temperature at which a liquid
becomes a gas is called the boiling
point.
Notice temperature is constant while ice melts!
10.3 Melting and boiling points of
common substances
Materials have a
wide range of
melting and
boiling points.
10.3 Sublimation
Sometimes a solid
can change directly
to a gas when heat
energy is added.
This process is
called sublimation.
10.3 Plasma
In the plasma phase,
matter becomes
ionized as electrons
are broken loose from
atoms.
The Sun is made of
plasma, as is most of
the universe, including
the Orion nebula.
Investigation 10C
Heat of Fusion of Ice
Key Question:
How much energy is required to melt a
certain mass of ice?
Television Technology
If you understand the
basic principles of
how a CRT (cathode
ray tube) television
works, then you can
begin to understand
how plasma and LCD
television works.