chapter 3 material on midterm. how do materials feel as they change state?
TRANSCRIPT
States of MatterChapter 3
Material on Midterm
How do materials feel as they change state?
Vanishing act
Objectives◦ Describe the properties shared by particles of all
matter◦ Describe three states of matter◦ Explain the differences between the states of
matter
Section 1: Three States of Matter
What are states of matter?◦ The States of matter are the physical forms in
which a substance can exist Solid Liquid Gas
Section 1: Three States of Matter
Particles of matter◦ Matter is made of small particles called atoms and
molecules◦ Always on the move◦ How they interact with each other determines
their state of matter
Section 1: Three States of Matter
What is a solid?◦ A solid is the state of matter that has a definite
shape and volume
◦ Particles smooshed together◦ Can only vibrate—stuck in place
Section 1: Three States of Matter
Types of solids◦ Crystalline solids have a orderly, 3D arrangement
in a repeating pattern Ice, diamond, iron
◦ Amorphous solids have no special arrangement Glass, rubber, wax
Section 1: Three States of Matter
What is a liquid?◦ A liquid is the state of matter than has a definite
volume but takes the shape of its container
◦ Little space in between particles◦ Can slide past another
Section 1: Three States of Matter
Liquid characteristics◦ Surface tension is a force that acts on the
particles at the surface of a liquid
◦ Viscosity is a liquid’s resistance to flow
Section 1: Three States of Matter
What is a gas?◦ A gas is the state of matter that has no definite
shape or volume
◦ Molecules move super fast◦ Not really held together at all
Section 1: Three States of Matter
Other States/Phases Plasma is the most common state of matter in the universe (99%).
It is a highly charged (ionized) gas.
Present in stars.
Bose-Einstein Condensate – at very low temperatures (near -273°C) atoms behave as though they were a single particle.
Check it out
State of Matter Definite Shape? Definite Volume?
Solid
Liquid
Gas
Section 1: Three States of Matter
Section Review◦ Please answer the objectives on your objective
summary sheet
1. Describe the properties shared by particles of all matter
2. Describe three states of matter
3. Explain the differences between the states of matter
Section 1: Three States of Matter
Objectives:◦ Describe the three factors that affect how gases
behave◦ List the variables involved in Boyle’s law and
Charles’s law◦ Predict how a change in pressure or temperature
will affect the volume of a gas
Section 2: Behavior of Gases
What factors affect how gases behave?◦ Temperature
◦ Volume
◦ Pressure
Section 2: Behavior of Gases
Temperature◦ Temperature is a measure of how fast the
particles in an object are moving The faster the particles move, the more energy they
have
Increase temperature….increase pressure Increase temperatures…increase volume
Section 2: Behavior of Gases
Volume◦ Volume is the amount of space that an object
takes up
◦ Volume of a gas depends on its container
◦ Decrease volume…increase pressure…pop!◦ Increase volume…decrease pressure
Section 2: Behavior of Gases
Pressure◦ Pressure is the amount of force exerted on a
given area of surface
◦ The more particles…the more pressure
Section 2: Behavior of Gases
Section 2: Behavior of Gases
Gas behavior laws◦Boyle’s Law
Involves volume and pressure
◦Charles’s Law Involves temperature and volume
Section 2: Behavior of Gases
Boyle’s Law
Section 2: Behavior of Gases
Boyle’s Law
Section 2: Behavior of Gases
What is Boyle’s Law?◦ Boyle’s Law states that a fixed amount of gas at
a constant temperature, the volume of a gas is inversely related to the pressure Inversely = opposite
So… As pressure increases, volume decreases As pressure decreases, volume increases
Section 2: Behavior of Gases
Charles’s Law
Section 2: Behavior of Gases
Charles’s Law
Section 2: Behavior of Gases
What is Charles’s Law?◦ Charles’s Law states that for a fixed amount of
gas at a constant pressure, the volume of gas changes in the same way that the temperature changes
◦ So… As temperature increases, volume increases As temperature decreases, volume decreases
Section 2: Behavior of Gases
Charles Law – soap
Charles Law - Egg
Section Review◦ Please answer the objectives on your objective
summary sheet
1. Describe the three factors that affect how gases behave
2. List the variables involved in Boyle’s law and Charles’s law
3. Predict how a change in pressure or temperature will affect the volume of a gas
Section 2: Behavior of Gases
Objectives◦ Describe how energy is involved in changes of
state◦ Identify phase changes as endothermic or
exothermic◦ Describe what happens during melting and
freezing◦ Compare evaporation and condensation◦ Explain what happens during sublimation and
deposition◦ Identify the two changes that can happen when a
substances loses or gains energy◦ Interpret a phase change(heating curve) diagram
Section 3: Changes of State
A change of state is the change of a substance from one physical form to another
Section 3: Changes of State
The six changes of state◦ Melting (SL)◦ Freezing (LS)
◦ Evaporation (LG)◦ Condensation (GL)
◦ Sublimation (SG)◦ Deposition (GS)
Section 3: Changes of State
We can either add or remove energy to get changes of state
If we add, we call it endothermic
If we remove, we call it exothermic
Section 3: Changes of State
Melting is the change of state from a solid to a liquid◦ Adding energy to a solid increases its energy◦ Particles move faster, move away from each other
The melting point is the temperature at which a substance changes from a solid to a liquid
Section 3: Changes of State
Item Melting temperature (C)
State of matter at room temperature (25C)
Water 0 C
Table salt 801 C
Nitrogen -210 C…-159C boiling
Freezing is the change of state from a liquid to a solid◦ We remove energy—molecules slow down◦ The freezing point is the temperature at which
this happens
Section 3: Changes of State
Evaporation is the change of a substance from a liquid to a gas◦ We add energy—molecules speed up◦ Does not have to have bubbles◦ Can occur just at the surface
Boiling is the change of a liquid to a gas (vapor) throughout the whole liquid
Section 3: Changes of State
Condensation is the change of state from a gas to a liquid◦ We remove energy—molecules slow down◦ Condensation point is the temperature at which a
gas becomes a liquid Same as boiling point
Section 3: Changes of State
Sublimation is the change of state from which a solid changes directly into a gas◦ We add a LOT of energy—molecules speed up a
lot
◦ Dry ice
Section 3: Changes of State
Change of temperature versus change of state◦ When energy is added…
Either the temperature changes OR the state changes
Not both!
Section 3: Changes of State
Section 3: Changes of State
When you add heat to a solid…◦ …the temperature increases until the melting
point You still add heat…
◦ …the temperature stays while the solid melts You now add heat to a liquid…
◦ …the temperature increases until the boiling point You still add heat…
◦ …the temperature stays while the liquid boils You now add heat to a gas…
◦ …the temperature will just keep increasing!
Section 3: Changes of State
Section 3: Changes of State
Section 3: Changes of State
State change Starting state
Ending state
Energy added or removed
Endothermic or exothermic
Melting
Freezing
Evaporation
Condensation
Sublimation
Deposition
Section 3: Changes of State
Section Review◦ Please answer the objectives on your objective summary
sheet
1. Describe how energy is involved in changes of state
2. Identify phase changes as endothermic or exothermic
3. Describe what happens during melting and freezing
4. Compare evaporation and condensation
5. Explain what happens during sublimation and deposition
6. Identify the two changes that can happen when a substances loses or gains energy
7. Interpret a phase change(heating curve) diagram
Section 3: Changes of State