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.