Transcript States of Matter

Chapter 2
States of Matter
Matter
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Anything that takes up space
and has mass
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Three states of matter:
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Composed of tiny particles
What are they called????????
Solid, liquid, gas
Plasma is the fourth state
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Occurs only at very high
temperatures and is not common
on Earth
Movement of Particles
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Atoms are always moving in matter
They move faster when they have more
kinetic energy (energy of movement) and
slower when they have less kinetic energy
More heat = More energy
Solids
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Matter with definite shape and
volume because particles are packed
closely together and merely vibrate in
place
Very little kinetic energy in particles
 So they move very slowly
Particles of solids arranged in one of
2 ways:
 Crystals - arranged in repeating,
3-D patterns
 Amorphous - have random
arrangement
Liquids
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Matter with a definite volume but no definite shape
 Particles move more freely than those of a solid
Particles have more kinetic energy than particles in solid
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So they are moving faster than in a solid
Viscosity is a liquids resistance to flow
 Increases when particles are more strongly attracted
to each other
Surface Tension is the tendency of molecules of a liquid
to stick together
 Due to uneven forces acting on particles
Gasses
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Matter that does not have a
definite shape or volume
Diffusion is the movement of
particles from an area of high
concentration to an area of low
concentration
 If you spray cologne, the smell
will eventually spread out.
Gas particles spread out evenly
and as far apart as possible
 They will fill a container.
Most kinetic energy
 So they are moving the fastest
Section 1 Review
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5.
Define matter in your own words and give three
things containing matter.
Describe the movement of particles within solids,
liquids, and gases.
Why do liquids flow?
A scientist places 25 mL of a yellow substance into
a 50-mL container. The substance quickly fills the
entire container. In which state of matter is the
substance? Why?
Two of the three common states of matter can be
grouped together. Which two states share a similar
property? Explain.
Changes of State
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Particles are in constant motion
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Amount of movement depends on their kinetic
energy (energy of movement)
Thermal energy is the total energy of all the
particles in a sample of matter
Temperature is the average kinetic energy of
particles in a substance
Heat is the movement of thermal energy from
a substance with a higher temperature to one
with a lower temperature
Changes of State
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Specific Heat is the
amount of heat needed to
raise the temperature of 1
g of a substance 1°C
For example, the specific
heat of water is equal to
one calorie
Changes of State
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Matter can change states as energy is absorbed or released
A change from the solid to the liquid state is called melting
 Is energy absorbed or released?
 What happens to the particles?
A change from the liquid to the solid state is called freezing?
 Is energy absorbed or released?
 What happens to the particles?
Changes of State
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A change from liquid to gas is called
vaporization
Boiling is vaporization which occurs below the
liquid’s surface at its boiling point
Evaporation is vaporization which occurs at
the surface of a liquid
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Molecules must be at or near the surface at the
right speed to evaporate
What about energy?
What about particles?
Changes of State
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Condensation is a change
from a gas to a liquid
 What about energy?
 What about particles?
During sublimation, the
surface particles of a solid
gain enough energy to
become a gas.
Pressure
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Pressure equals the force exerted on a
surface divided by the total area over which
the force is exerted
 Pressure(P) = Force(F) / Area(A)
If force increases over an area, the pressure
increases
If force over an area decreases, the pressure
decreases
Section 2 Review
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6.
How are thermal energy and temperature similar?
How are they different?
How does a change in thermal energy cause matter
to change from one state to another?
During which three changes of state is energy
absorbed?
What are two types of vaporization?
Do particles of gold move faster in the liquid or the
solid state? Liquid or gas?
How can the temperature of a substance remain
the same even if the substance is absorbing
thermal energy?
Pressure
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Atmospheric pressure is the
air that presses down on
the Earth with force
Pressure can be balanced
as the pressure pushing
down equals the pressure
pushing up
As altitude increases, air
pressure decreases
 That’s why it’s colder at
higher altitudes
Gas Pressure in Containers
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Gas pressures in a closed container changes
with volume and temperature changes
Decreasing volume increases pressure
Increasing volume decreases pressure
Increasing temperature increases pressure
Decreasing temperature decreases pressure
Boyle’s Law
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At a constant
temperature,
pressure times
volume is a constant
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They are inversely
related (as one goes
up, the other goes
down)
Charles and Gay-Lussac’s Law
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At a constant
pressure, Volume = a
constant times
temperature
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Volume and
temperature are
directly proportional
(as one goes up, the
other goes up)
The Ideal Gas Law
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Charles’ and Boyle’s Law Combined
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pV=nRT (n and R are constants)
Pressure x Volume is proportional to
Temperature
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pV~T
Buoyant Force
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An upward force on an object immersed in a
fluid
Archimedes’ principle states that the buoyant
force on an object is equal to the weight of
the fluid displaced by the object
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If a boat displaces 10,000 N of water, then the
buoyant force upward from the water will be
10,000 N (it will seem 10,000 N lighter)
Density
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Density is mass divided by volume
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D = M/V
It’s all about the love
An object will float in a fluid that is denser
than the object
An object with the same density as the fluid
will stay the same level in the fluid
An object will sink in a fluid that is less dense
than the object
Density and States of Matter
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Which is more dense: ice, liquid water, or
water vapor?
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As particles of water get more energy (from heat),
they move faster and spread apart more.
As particles move faster, they spread apart
and become less dense.
Where is the air the least dense? Why?
The air particles are farther apart at high
altitudes and are less dense (due to pull of
gravity)
Pascal’s Principle
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When a force is applied to a
confined fluid, an increase in
pressure is transmitted equally to
all parts of the fluid
Hydraulic systems allow people to
lift heavy objects with relatively
little force
When squeezed, liquids will be
pushed out of a force pump, a
closed container with a hole in it.
Section 3 Review
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6.
7.
What happens to pressure as the force exerted on a given
area increases?
How does atmospheric pressure change as altitude increases?
How does density change?
An object floats in a fluid. What do you know about the
buoyant force on the object? How does the density of the
object compare with the density of the fluid?
Why does wood float in water?
Which is more dense: the crust of the Earth or the oceans?
What would the Earth look like if the oceans were more
dense than the crust?
All of the air is removed from a sealed metal can. After the air
has been removed, the can looks as if it were crushed. Why?