1. Chapter 10 Kinetic Theory of Matter

2. Objectives 10.1 Compare characteristics of a solid, liquid, and gas. 10.1 Relate the properties of a solid, liquid, and gas to the kinetic theory of matter 10.1 Distinguish among an amorphous material, liquid crystal, and plasma

3. Objectives 10.2 Interpret changes in temperature and changes of state of a substance in terms of the kinetic theory of matter 10.2 Relate Kelvin and Celsius scale 10.2 Analyze the effects of temperature and pressure on state changes 10.2 Identify and understand types of intermolecular forces (LDF, Dipole-Dipole, Induced dipole) for molecules

4. Solid Liquid Gas Revisited Solid: Fixed atomic position Liquid/Gas: No fixed atomic position Solid/Liquid: Atoms and molecules hold onto one another Ideal Gas: No attraction at all for each other

5. Same Temperature means Same Kinetic Energy All matter is in random and constant motion. Not all matter or molecules within the same state of matter move at the same speed The heavier a molecule is, the smaller its speed – Heavier gases diffuse slower than light gases – Heavier solid atoms jiggle less than lighter solids

6. Other States of Matter Liquid Crystals – When some solids melt, they don’t melt in all dimensions, remain a solid in at least one dimension. Some keep their shape in one of the three dimensions. These can then be manipulated by electric charge

7. Other States of Matter Amorphous Materials – Have an incomplete, or random crystal lattice. – Examples include peanut butter, glass (when heated), cotton candy, pudding – Distinction can be difficult, many everyday objects you would consider solid could be classified in this way – If it is a mixture of solids/liquids (hard to tell), it is amorphous

8. Other States of Matter Plasmas – Ionized gas – Most common in universe, not on earth – Occurs in stars

9. Temperature and Particle Motion

10. Same Temperature, Different Gases

11. Temperature Scales Three Scales: Kelvins, Celsius, Fahrenheit Kelvins  Absolute Temperature Scale, it has a value of 0 at absolute 0 – Important to use an absolute temperature scale in many calculations otherwise you would find negative volumes of air as well as other unfortunate mistypes in the calculator – Absolute Zero: All molecules have zero kinetic energy

12. Temperature Scales Celsius  Has same slope as Kelvins, just starts below it 273 degrees. – Water freezes at 0 C and boils at 100 C, convenient Fahrenheit  The American scale, based on ability to detect temperature change Equation above is black, but should be green

13. Quick Questions If the temperature of the room is at equilibrium, which state of matter in this room has the most kinetic average per particle? Can an individual molecule touch absolute zero? Defend your rationale. 373 Kelvin is what temperature Celsius?

14. Diffusion/Effusion Diffusion – Process of gas molecules spreading out due to random motion Effusion – Process of gas molecules escaping through a tiny opening (why balloons go flat) – What goes flat faster: Helium or Normal filled balloon?

16. Distillation Technique used to separate mixtures based on difference in boiling points – Example: If water and another liquid are mixed, if you boil them, the one with a lower boiling point evaporates first until it is all gone before temperature rises again

19. Temperature is an Average Therefore, some molecules are able to evaporate or melt before the temperature reaches that point – Some water evaporates (boils) before 100 C

20. Changes of States Solid to Liquid  Melting Solid to Gas  Sublimation – Dry Ice and Moth Balls Liquid to Gas  Evaporation Gas to Liquid  Condensation Gas to Solid  Deposition – Frost Liquid to Solid  Freezing

22. Vapor Pressure How much of a liquid evaporates? – That is vapor pressure – The liquid molecules which turn to gas exert a pressure (as a gas does). – The warmer it gets, the more that evaporates, the larger the pressure Polar molecules = Lower Vapor pressures – Have a difficult time escaping from one another

24. Vapor Pressure As the temperature increases (for the liquid), the vapor pressure increases as more and more of the liquid can evaporate

26. How much heat to evaporate? Heat of Vaporization: Energy required to make a substance evaporate – Also energy released when condensing Heat of Fusion: Energy required to make a substance melt – Also energy released when freezing

27. Lots of energy to evaporate Why we feel cold after being in the pool

29. Some Math How much energy will it take to melt 1.0 gram of ice? Heat of fusion for water is 334 J/g If you have 200 grams of water that the ice melts in, what is the temperature change of the water? The specific heat of water is 4.18 J/g