1. CHEM 121 Chapter 7 Winter 2014 1

2. Kinetic Molecular Theory of Matter Explains matter in various states 1. 2. 3. 4. 5. 2

3. States of Matter Matter: Physical states: 3 Properties of Matter:

4. Solids Strong attractive forces ( ) Properties: _________________ density _________________ compressibility _________________ shape _________________ thermal expansion 4

5. Liquids Medium forces ( ) Properties: _________________ density _________________ compressibility _________________ shape _________________ thermal expansion 5

6. Gases No attractive forces High kinetic E: Properties: _________________ density _________________ compressibility _________________ shape _________________ thermal expansion 6

7. Measuring Pressure Pressure (P) http://encarta.msn.com/media_461532488_ 761573986_1_1/mercury_barometer.html Barometer: 7

8. Units of Pressure pascal atmosphere Millimeter of mercury psi, pounds per square inch (engineering) 8

9. Gas Laws 9 4 Variables: P: T: V: n:

10. Boyle’s Law volume occupied by a gas is __________ related to its pressure 10

11. A sample of gas has a volume of 100.0 mL at 1.0 atm. If we increase the pressure to 2.0 atm, what is the new volume of the gas (T is constant)? 11 3-minute practice

12. Charles’s Law volume of a gas is __________ related to its temperature (K) 12

13. A sample of gas has a volume of 100.0 mL at 27 ˚C. If we heat the gas to 54 ˚C (keeping P constant), what is the new volume of the gas? 13 3-minute practice

14. Gay-Lussac’s Law At constant volume, pressure is __________ related to temperature Combined Gas Law: 14

15. Avogadro’s Law The volume occupied by a gas is __________ proportional to the amount (mol) of gas (fixed T & P) At fixed T & P: equal volumes of any ideal gas have… 15

16. Gas Behavior at STP STP: Standard Molar Volume 16

17. What is the volume (mL) of 0.10 g of helium gas at STP? 17 3-minute practice

18. Ideal Gas Law Combine: –Boyle’s Law –Charles’s Law –Avogadro’s Law Solve at STP… 18

19. A tank filled with methane at 23 ˚C and 0.991 atm is fitted with a safety valve that opens if internal pressure exceeds 1.00 x 10 3 torr. When the tank is placed in boiling water at exactly 100. ˚C, will the safety valve open? Initial: T = P = n = V = Final: T = P = n = V = 19

20. A sample of gas occupies 105 mL at 0.903 atm. If temperature remains constant, what is the volume (in L) at 26.4 kPa? Initial: P = V = n = T = Final: P = V = n = T = 20

21. Each gas in a mixture acts like it is the only gas present Dalton’s Law of Partial Pressures: Mixtures of Gases Example: When water vapor added to pure air…. Each gas exerts __________________________________ 21

22. Graham’s Law Effusion: gas leak through hole Diffusion: spontaneous mixing of gases 22

23. Which will deflate more quickly: a balloon filled with helium or nitrogen? 23 3-minute practice

24. Changes of State 24 Intermolecular Forces:

25. dipole-dipole polar molecules acting like magnets if between H and N, O, or F _______________ O Intermolecular Forces 25 H H O H H O H H London Dispersion forces

26. Vapor Pressure As a liquid evaporates: But if closed container… 26 Vapor Pressure:

27. Boiling As you increase T, vapor pressure _____________ If vapor pressure reaches atmospheric pressure… 27

28. Sublimation and Melting Solids have vapor pressures too! –Typically low or high? Sublimation: Melting: Decomposition: 28

29. Heating and Cooling Curves Plateaus: Slopes: 29

30. Specific Heat (SH) Amount of heat to raise the T of ___ of a substance by ____ 30 How much energy is needed to raise the temperature of 20.0 g of iron by 14.5 °C?

31. Changes of State Equations Heat of Fusion: Heat of fusion for water = 80 cal / g Heat of Vaporization: Heat of vaporization for water = 540 cal / g 31

32. Solid State 32

33. Solid State 33