1. Chapter 3 Material on Midterm

2.  How do materials feel as they change state?

3.  Objectives ◦ Describe the properties shared by particles of all matter ◦ Describe three states of matter ◦ Explain the differences between the states of matter

4.  What are states of matter? ◦ The States of matter are the physical forms in which a substance can exist  Solid  Liquid  Gas

5.  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

6.  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

7.  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

8.  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

9.  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

10.  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

11.  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

12. State of MatterDefinite Shape?Definite Volume? Solid Liquid Gas

13.  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

14.  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

15.  What factors affect how gases behave? ◦ Temperature ◦ Volume ◦ Pressure

16.  Temperature 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

17.  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

18.  Pressure Pressure ◦ Pressure is the amount of force exerted on a given area of surface ◦ The more particles…the more pressure

20.  Gas behavior laws ◦ Boyle’s Law  Involves volume and pressure ◦ Charles’s Law  Involves temperature and volume

21.  Boyle’s Law

23.  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

24.  Charles’s Law

26.  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

27.  Charles Law – soap Charles Law – soap  Charles Law - Egg Charles Law - Egg

28.  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

29.  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

30.  A change of state is the change of a substance from one physical form to another

31.  The six changes of state ◦ Melting (S  L) ◦ Freezing (L  S) ◦ Evaporation (L  G) ◦ Condensation (G  L) ◦ Sublimation (S  G) ◦ Deposition (G  S)

32.  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

33.  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 ItemMelting temperature (C) State of matter at room temperature (25C) Water0 C Table salt801 C Nitrogen-210 C…-159C boiling

34.  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

35.  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

36.  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

37.  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 Dry ice

38.  Change of temperature versus change of state ◦ When energy is added…  Either the temperature changes  OR the state changes  Not both!

40.  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!

42. Section 3: Changes of State

43. State changeStarting stateEnding stateEnergy added or removed Endothermic or exothermic Melting Freezing Evaporation Condensation Sublimation Deposition

44.  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