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CHAPTER 12

CHAPTER 12. STATES OF MATTER. 4 STATES OF MATTER. Gases Liquids Solids Plasma ( Ice Ice Baby Rap ) Dance. KINETIC MOLECULAR THEORY. (KMT)- describes the behavior of particles in terms of their motion Explains the effect of temp. and pressure on matter KMT video

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CHAPTER 12

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  1. CHAPTER 12 STATES OF MATTER

  2. 4 STATES OF MATTER • Gases • Liquids • Solids • Plasma • (Ice Ice Baby Rap) • Dance

  3. KINETIC MOLECULAR THEORY • (KMT)- describes the behavior of particles in terms of their motion • Explains the effect of temp. and pressure on matter • KMT video • Molecules in Motion Song

  4. Assumptions for KMT- gases • 1. Particle size- all matter is composed of small particles • Between the particles is empty space • There are no attractive or repulsive forces between particles

  5. 2. Particle motion- particles are in constant random motion • Travel in straight line paths • Change direction upon collision • Collisions are elastic (no net loss of kinetic energy [KE])

  6. 3. Particle energy- kinetic energy (KE) is a factor of mass and velocity of a particle • KE= energy an object possesses because of its motion • Formula: KE = 1/2mv2 • Depends on mass and velocity

  7. PRESSURE • Dependent on force of collision and the # of collisions • Pressure = force area • Atmospheric pressure- (Barometric) results from the collisions of air molecules w/objects on earth • Varies depending on location

  8. Tools for measuring pressure • Manometer = device use to measure pressure of enclosed gas

  9. Barometer = special manometer used to measure atmospheric pressure • Developed by Torricelli Aneroid barometer

  10. Standard Atmospheric Pressure • Average pressure at sea level • = 760 mmHg (millimeters of mercury) • Units for pressure: • Pascal (Pa) = 1 Newton m2 • 1000 Pa = 1kPa • Standard atmospheric pressure = 101.3 kPa • Also known as 1 atm (atmosphere)

  11. 216.9 kPa 760 mmHg 1627 mmHg 101.3 kPa 763 mmHG 101.3 kPa 102 kPa 760 mmHg Pressure Conversion Factor 101.3 kPa = 1 atm= 760 mmHg = 760 torr = 14.7 psi Example: 216.9 kPa = _____________ mmHg 763 mmHg = ______________kPa

  12. TEMPERATURE • DEFINITION: measure of the average KE of the particles in a substance (> temp. = > KE) • If you have 2 substances at same temp., they must have the same average KE, so the molecule w/the less mass will move faster • Ex: O2 and H2 at 20°C 32 g/mole 2 g/mole -so H2 has the > velocity

  13. Absolute zero KE KE = 0 -273 0 100 Temp. °C ABSOLUTE ZERO • Temperature at which the motion of particles ceases (stops moving) • Absolute zero = -273°C

  14. Supernova remnent (star death) • Spitzer Space Telescope • Launched August 24, 2003 • With this new infrared telescope, only the science instrument chamber and a compact cryostat will be cold at launch, chilled to about 1.5 Kelvin (-272 Celsius, or -457 Fahrenheit). Following launch from Cape Canaveral Air Force Station in Florida, the spacecraft cooled in the deep recesses of space for about five weeks. The observatory uses the vapor from the boil-off of its cryogen fluid to cool the telescope assembly down to its optimal operating temperature of 5.5 Kelvin (-268 Celsius, or -450 Fahrenheit). • cryogen depletion date 5/15/09 (now in warm mission- two of its arrays still working) • James Webb Vega (dust cloud around)

  15. A Joke Break… Q: What did the thermometer say to the graduated cylinder? A: "You may have graduated but I've got many degrees" Ha, Ha, Ha, again I crack myself up.

  16. TEMPERATURE SCALES • Farenheit- 32°F= freezing water; 212°F= boiling water • Celcius- based scale on freezing point of water = 0°C; boiling = 100°C • Kelvin- based on absolute zero; 0 K = -273°C (a change of 1 degree on K scale is same on °C)

  17. Conversion factor K = °C + 273 Example: 25 ° C = ___________K 400 K = ____________ °C 298 127

  18. Use for temperature: • Determine direction of energy flow • When a cool object (less KE) is in contact w/a warmer object (higher KE) the energy of the warmer object will transfer to the cooler until the KE is equal or same temp.

  19. Heat (em cee delta tee song) • The energy transferred due to a temp. difference • Physical and chemical changes are accompanied by energy changes • Heat (Q) – energy transferred from a hotter object to a cooler object due to a temp. difference

  20. Exothermic- released energy; gives off heat or light • Endothermic- absorbs energy; cool to the touch

  21. LAW OF CONSERVATION OF ENERGY • ENERGY CAN BE CONVERTED FROM ONE FORM TO ANOTHER BUT IT IS NOT CREATED NOR DESTROYED • Activation energy = the minimum amount of energy needed to get a reaction started

  22. UNITS FOR HEAT • Joule (J)- quantitative measurement of an energy change or heat • English system uses a calorie (cal) • Conversion factors • 1 cal = 4.18 J • 1000 cal = 1 Cal (food value) = 1 kcal little”c” big “C” • Ex. 1 tic tac = 4180 J or 1 Cal

  23. Orange Juice 340 kJ (80 Cal)

  24. SPECIFIC HEAT Constant • The heat needed to raise the temp. of 1 g of a substance 1°C or 1 K • Represented with the letter “c” • Unit= J/g°C • Ex: c water = 4.18 J/g°C

  25. MEASURING ENERGY CHANGES • CALORIMETER- device used to measure energy changes • Usually contains water • Measures heat absorbed or released • Follows Law of conservation of Energy

  26. 1. Formula for heat Q = m c rT • Heat lost or gained = (mass in grams)(specific heat constant)(change in temp)

  27. How much heat is needed to heat up 145g of water from 25.0 C to 95.0 C? Specific heat of water= 4.18 J/g C.

  28. 2. Finding specific heat of unknown substance • Heat lost = heat gained by water • Q lost = Q gained • Q lost = mcrT Q gained = mcrT • so, mcrTlost = mcrTgained

  29. A piece of metal with a mass of 35.0 g and a temperature of 100.0 C is placed into 105.0 g of water at a temperature of 25.0C. After the metal cools the final temperature of the system is 31.5C. What is the specific heat of the metal?

  30. Lab- Specific Heat • Data (w/ units) • Calculations: (do for each metal) • 1. Mass of water (data #3- data #2) • 2. Change in temp. water (data #6- data #5) • 3. Change in temp metal (data #4 – data # 6)

  31. mcrTlost = mcrTgained • (data #1) c (calc #3)=(calc # 1) 4.18 (calc #2) • (solve for c) • % Error= O (above) – A x 100 • A • Also: Questions & Conclusion

  32. What is the pressure in atmospheres if the pressure is 742 mm Hg?

  33. If a book with a force or weight of 25 N is laying flat on a table covers a surface that is .20 m by .35 m, what is the pressure it is applying to the table?

  34. A piece of unknown metal with mass of 14.9 g is heated to 100.0 C and dropped into 75.0 g of water that was at 20.0 C. The final temperature of the system is 28.5 C. What is the specific heat of the metal?

  35. Lab- Calories of FoodHow to use the Lab Pro • Data (w/ units) • Calculations (one for each food item) • 1. Change in temp (data 7- data 8) • 2. . mass of water (data #4- data #5)

  36. 3. Heat lost by food= Heat gained water • Q lost= mc Δ t (water) • Q = (calc. #2) (4.18) (calc #1) • 4. Convert heat lost (joules to cal) • Calc #3/ 4.18 • 5. Mass of food burned • (data #1- data#2)

  37. 6. Heat lost by 1 gram of food • calories (calc #4) / mass of food (calc #5) • 7. % Error • Calc #6- accepted value x 100 Accepted value Questions (1,2) and conclusion

  38. STATES OF MATTER Describing the kinetic theory as it applies to the states of matter Dance

  39. INTRAMOLECULAR FORCES • Attractive forces that hold particles together in ionic or covalent bonds (intra= within)

  40. INTERMOLECULAR FORCES • Forces of attraction between particles (holding similar particles close together like in a solid or liquid) • Intermolecular forces video • Types: • van der Waals • Dispersion forces • Dipole-dipole forces (polar molecules) • Hydrogen bond (special type of dipole-dipole force)

  41. GAS Gas video • Independent particles moving in straight lines • Change direction with collision • Travel randomly • Assume shape and volume of container • Large amount of empty space • No attraction force • compressible

  42. Gas properties: • Fluidity- gas particles glide and flow past each other • Expansion- fill any container • Compressibility- can decrease volume • Diffusion- spontaneous mixing of 2 gases; flow until evenly dispersed; flow from area of higher concentration to lower

  43. Graham’s Law of Diffusion- proportion comparing diffusion rate • Rate A = molar mass B Rate B molar mass A • Ex: HCl and NH3 Molar mass = 36.5 molar mass = 17.0 Rate NH3 = molar mass HCl Rate HCl molar mass NH3 = 36.5 17.0 = 1.5 So NH3 diffuses 1.5 x faster

  44. LIQUID • Properties video • Form of matter that flows, has constant volume and takes the shape of its container • Particles are in motion but slower than gases (slip/slide motion)

  45. Particles are held together by weak intermolecular forces (don’t have enough KE to break away from the attraction) • Reduced amount of empty space

  46. Properties of Liquids • Density and compression • Liquids are denser than their gas phase • Liquids can be compressed, but an enormous amount of pressure must be applied to reduce the volume by just a small proportion

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