States of Matter: Kinetic Molecular Theory

1. States of Matter: Kinetic Molecular Theory Holt McDougal Physical Science C3S1: Matter and Energy Glencoe Science Physical Science C16S1: Kinetic Theory

2. NGSSS Benchmark(s) • SC912P12.11 • Describe phase transitions in terms of kinetic molecular theory • SC912P8.1

3. Learning Objectives • What makes up matter? • What is the difference between a solid, a liquid, and a gas? • What kind of energy do all particles of matter have? • How do particles move in the four states of matter? • How do particles behave at the melting and boiling points of matter?

4. Characteristics of Matter • Has mass • Has volume • Made of atoms • Atoms in constant motion

5. Kinetic Molecular Theory of Matter • All matter is made of particles that are in constant motion • “Stuff is moving all the time”

6. Kinetic Theory 2 • The faster particles move, the higher the temperature of the substance. • “Fast moving stuff is hotter than slow moving stuff.”

7. Kinetic Theory 3 • At the same temperature, more massive particles move more slowly than less massive ones. • “Big stuff is slower than small stuff at the same temperature.”

8. What explains how particles in matter behave? • Law of Conservation of Mass • Law of Kinetic Movement • Kinetic Molecular Theory • None of the above

9. What is Thermal Energy? • Energy  ability to change/move matter • Total energy of the particles in a material • TE = KE + PE • If temperature is lowered, particles will have less thermal energy

10. Average Kinetic Energy • Temperature  avg of how fast particles are moving • Molecules have kinetic energy at all temperatures (even absolute zero)

11. What two things comprise thermal energy? • Potential movement and Kinetic energy • Kinetic movement and Potential energy • Potential movement and Kinetic movement • Potential energy and Kinetic energy

12. Common States of Matter • Solid, liquid, gas • Definite  something does not change • Variable  something can change

13. Solids • Definite volume • Definite shape • Strong attraction keeps particles in place • Particle arrangement establishes chemical and physical properties

14. Solid to Liquid: How? • Melting point  temp for solid to begin turning to liquid • Particles slip out of ordered arrangement • Heat of Fusion  amt of energy needed to change a substance from a solid to a liquid at its melting point

15. Liquids • Particles faster than solids • Flow freely • Definite volume • Variable shape

16. Liquid to Gas: How? • Particles have enough energy to escape attractive forces • Evaporation  particles at surface & travel away • Boiling point  temp at which pressure of the vapor in the liquid = external pressure on surface of liquid • Heat of vaporization  amt of energy needed for liquid at its boiling point to become a gas

17. Gases • Overcome attractive forces • Variable shape • Variable volume

18. How would you respond? • What is the temperature at which a solid begins to turn into a liquid called? • Which particles have the least kinetic energy? • What do particles need in order to overcome the force of pressure and become a gas? • How does the movement of particles in a liquid differ from the movement of particles in a solid? • What causes a solid to have a definite volume and shape?

19. Fluid: What is it? • State of matter with variable shape • Liquids • Gases

20. Plasma • Matter made up of positively and negatively charged particles (i.e., ionized particles) • Neutral • Conducts electricity • Stars, lightning bolts, neon and fluorescent tubes, auroras

21. Thermal Expansion • Increase in the size of a substance when the temperature is increased • “Hot stuff moves faster and takes up more space.”

22. Solid or Liquid: Which? • Amorphous solid  no melting point; soft over a range of temperatures • Glass • Plastic • Liquid Crystals  maintain ordered structure from solid to liquid state

23. What do you think? • Describe the movement of particles in a fluid. • Is plasma a fluid? Explain your answer. • Why do all particles of matter have kinetic energy? • Which of the three common states of matter has particles with the most kinetic energy? • Why do all particle of matter have kinetic energy? • What does temperature measure?

24. Changes of State of Matter Holt McDougal Physical Science C3S2: Matter and Energy

25. Learning Objectives • What happens when a substance changes from one state of matter to another? • What happens to mass and energy during physical and chemical changes?

26. What Causes Matter to Change States? • Change of state  from one physical form to another • Caused by transfer of energy • Identity of substance remains the same

27. Adding and Removing energy • Heating  adds energy • Adding NRG  causes particles to move more quickly • Removing NRG  causes particles to move more slowly

28. Temperature and Energy • Adding NRG  increases kinetic energy of the particles • Removing NRG  decreases kinetic energy of the particles • Temperature  measure of the avg kinetic energy

29. Think fast! • What does “hot” mean for temperature? • What will removing all kinetic energy do to a gas?

30. Changes of State That Require Energy • Melting  from solid to liquid • Melting point  particles have enough nrg to break from rigid positions • Melting point  can change if pressure changes

31. Evaporation • Change from liquid to gas • Boiling  evaporation at specific temp and pressure • Boiling point  temp at which liquid boils

32. Sublimation • Change from solid to gas • Example: • Solid CO2 –(room temp) Gas CO2

33. What’s Your Answer? • What are three changes of state that require energy? • Melting • Boiling • Subliming

34. Changes of State That Release Energy • Condensation  from gas to liquid • Condensation point  temp to chg from gas to lqd • Condensation  often happens when gas touches cool surface (e.g., vapor touches cold glass and becomes water droplets)

35. Freezing Point • Freezing  chg from lqd to solid • Freezing point  temp at which substances freezes • Freezing point = Melting point = Freezing point • Add nrg to melt; release nrg to freeze

36. Do you recall? • What is the condensation point? • What is the melting point? • What is the boiling point? • What is the melting point? • What is the point? 

37. What Happens to Temperature During Changes of State? • Temp  does NOT chg during a chg of state • “When a substance loses or gains energy, either its temperature change or its state changes . . . (The) two changes do not happen at the same time.” (p. 51)

38. By the Way: Helpful Links • http://www.chem4kids.com/files/matter_intro.html • http://zonalandeducation.com/mstm/physics/mechanics/energy/heatAndTemperature/changesOfPhase/changeOfState.html

39. What Happens to Mass and Energy During Physical and Chemical Changes? • Law of Conservation of Mass • Law of Conservation of Energy • Conserve  to keep the same

40. Fluids Holt McDougal Physical Science C3S3: States of MatterFluids

41. Learning Objectives • How do fluids exert pressure? • What causes objects to float? • What happens when pressure in a fluid changes? • What affects the speed of a fluid?

42. What Are Fluids • Liquids and gases • Particles can move past each other • Exert pressure in all directions

43. What Is Pressure • With your neighbor, come up with a quick demonstration of pressure . . . • Pressure  amt of force exerted on a give surface area

44. Calculating Pressure • Divide force by area • Pressure = Force/Area; P=F/A • Pascal  SI unit for pressure • Newton  SI unit for force • 1 Pa = 1 N/m2 Is pressure a derived unit? Why/not?

45. Try Calculating Pressure Given a force of 20N over 60m2, how much pressure is being exerted? Try this on your whiteboard. • Write the formula: P = F / A • Substitute values: P = 20N/60m2 • Divide the units: P = N/m2 • Now, divide the quantities: 20/60= .33 • Assemble the answer: P = 0.33N/m2

46. What Causes an Object to Float? • Buoyant force  upward force fluids exert on matter • Archimedes’ Principle  “The buoyant force of an object equals the weight of the fluid that the object displaces.”

47. Do you remember . . . • What is pressure? • The amount of force exerted over an area • What is a Pascal? • The SI unit for pressure; 1Pa = 1N/m2 • Given area and pressure, how does one determine the number of Newtons required? • Since P=F/A, then F = P * A

48. Will It Sink or Float? By Weight By Density • Compare weight to buoyant force  why? • Floats  bouyant force > or = object’s weight • Sinks  bouyant force < or = object’s weight • Compare density of object to density of fluid • Floats  object is less dense than the fluid • Sinks  object is denser than the fluid • BTW, the density of water is . .. • 1 g/cm3 http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

50. What Happens When Pressure Changes in a Fluid? • What happens when you squeeze a balloon? • What happens when you squeeze a tube of toothpaste? • Pascal’s principle  “If the pressure in a container is increased at any point, the pressure increases at all points by the same amount.”