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Unit 10

Unit 10. Solids & Liquids Energy. Ice Cube Family Trip. Temperature ( o C). Heat energy added. Title the graph so you know what it is about. Make a KEY Blue = H 2 O Red = Paradichlorobenzene. Temperature ( o C). Start at 20 o C Use 5 lines = 10 o C. Use 2 line = ½ min.

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Unit 10

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  1. Unit 10 Solids & Liquids Energy

  2. Ice Cube Family Trip Temperature (oC) Heat energy added

  3. Title the graph so you know what it is about Make a KEY Blue = H2O Red = Paradichlorobenzene Temperature (oC) Start at 20 oC Use 5 lines = 10 oC Use 2 line = ½ min Time (min)

  4. There are 3 possible phases of matter: gas, liquid, and solid. When a substance is heated or cooled, it may undergo a phase change. ShapeVolume Gases not definite spreads out to fill any container Liquid not definite definite Solid definite definite

  5. There are 6 possible phase changes. Gas LiquidSolid When a gas is cooled it becomes a liquid, and when a liquid is heated it becomes a gas, both occur at the Normal Boiling Point (temperature) of the substance (at 1 atm of pressure) When a liquid is cooled it becomes a solid, and when a solid is heated it becomes a liquid, both occur at the Normal Melting Point (temperature) of the substance (at 1 atm of pressure) A calorie is the amount of heat energy needed to raise the temperature of 1 gram of water through 1 o C. A Joule is a unit of heat energy. 1 calorie = 4.18 joules

  6. Gas Sublimation Condensation Evaporation or Vaporization Deposition Melting or Liquefaction Liquid Solid Freeze or Solidification

  7. Heat equation Used when a substance undergoes a temperature change. • H = mcDT H = heat energy (joules) m = mass (grams) c = specific heat (joules required to raise 1 gram of the substance through 1 o C) DT = temperature change (DT = Tfinal – Tinitial) Cliquid H2O = 4.18 joule/gramoCCCu = 0.389 Csolid H2O = 2.09 CPb = 0.130 Cgas H2O = 2.09 CFe = 0.439

  8. How many joules are absorbed by 100 grams of water when it is heated from 40o C to 80o C?* Positive joules means that heat is absorbed by the substance. It is endothermic. How many joules are removed from 50 grams of water when it is cooled from 50o C to 30o C? * Negative joules means that heat is removed from the substance. It is exothermic.

  9. If all the Calories in a Double Whopper with cheese were used to heat a piece of Be, how hot would it get? Be = 27.98 g Double Whopper with cheese = 1061 Calories 1 Calorie = 1000 calorie in science 1 calorie = 4.18 joules

  10. How hot would a meteorite get? Meteorite = 3178 g Whopper has 4,434,980 joules

  11. Heat always flows from a higher temperature substance to a lower temperature substance. When a substance is melting, heat is used to separate the molecules. When a substance freezes, heat is removed, allowing the molecules to move closer together. During melting and freezing, the temperature of the substance does not change. These processes occur at the same temperature for a substance.

  12. Heat of Fusion equation Use when a substance is melting or freezing. H = Hf m H = heat (joules) Hf = heat of fusion (H2O = 335 joules/gram) m = mass (grams) What is the amount of joules involved when 20 grams of solid H2O (ice) melts to 20 grams of liquid H2O? * Hf is positive for melting

  13. Heat of Fusion equation Use when a substance is melting or freezing. H = Hf m H = heat (joules) Hf = heat of fusion (H2O = 335 joules/gram) m = mass (grams) What is the amount of joules involved when 35 grams of liquid H2O freezes to 35 grams of solid H2O (ice)? * Hf is negative for freezing.

  14. When a substance is evaporating (vaporizing), heat is used to separate the molecules. When a substance condenses, heat is removed, allowing the molecules to move closer together. During evaporating or condensing, the temperature of the substance does not change. These processes occur at the same temperature for a substance. Boiling occurs when the vapor pressure of the liquid is equal to the atmospheric (barometric) pressure above the liquid.

  15. Heat of Vaporization equation Use when a substance is evaporating or condensing. H = Hv m H = heat (joules) Hv = heat of vaporization (H2O = 2,260 joules/gram) m = mass (grams) What is the amount of joules involved when 50 grams of liquid H2O evaporates to 50 grams of gaseous H2O? * Hv is positive for evaporating (or vaporization).

  16. Heat of Vaporization equation Use when a substance is evaporating or condensing. H = Hv m H = heat (joules) Hv = heat of vaporization (H2O = 2,260 joules/gram) m = mass (grams) What is the amount of joules involved when 75 grams of gaseous H2O condensing to 75 grams of liquid H2O? * Hv is negative for condensing.

  17. How many joules are involved to change 100 g of ice at -50oC to steam at 150oC? Temperature (oC) Heat energy added

  18. Determination of heat of fusion of water 0 = DH ice + DH liquid H2O DH liquid H2O = m c DT DH ice = Hf m

  19. Black Box Data Recorder for Airplanes. The wax surrounding the recorder will melt when a fire occurs. During the melting, there is no temperature change, thus saving the data on the recorder.

  20. Heat gained by H2O in cup H = m c DT This heat is positive (+)H Calculate specific heat of metal slug H = m cDT Use the (-) of the heat for the cup mass of slug temperature change of slug c = - H_ m DT Relative % error – get actual value from specific heat chart that was given to you.

  21. Down 1. Critical 17. LeChatelier 24. Fluidity Across 10. Noncompressibility 30. Van der Waals 34. Dynamic Liquids Crossword Helps

  22. Clean Up! • Wash all glassware, (not metal or ceramic square) • Put clean paper in the bottom of drawer • Classroom equipment (thermometers, flint lighters, etc.) put on cart • Tighten screws of handle and lock on drawer • Wash safety glasses, label, and put in sterilizer

  23. Semester Review Answers • Kilogram (remember all the metric prefixes and what they mean) • 1.27 Kg = 1,270 g • 0.00278 = 2.78 x 10-3 • 5.0 x 1010 = 50,000,000,000 • Element = substance made of only one kind of atom • NaC2H3O2 • Na = 23.0 %Na = (23.0g/82.0g/mol) 100 = 28.05 % Na • 2 C = 24.0 %C = (24.0g/82.0g/mol)100 = 29.27 %C • 3 H = 3.0 %H = (3.0g/82.0g/mol)100 = 3.66 %H • 2 O = 32.0 %O = (32.0g/82.0g/mol)100 = 39.02 %O • 82.0 g/mol

  24. 7. CuSO4.5H2O Cu = 63.5 (90.0 g H2O/249.6 g/mol)100 = 36.06 % H2O S = 32.1 4O = 64.0 10H = 10.05 O = 80.0 249.6g/mol8. One mole of any element has 6.02 x 1023 atoms One mole of any compound has 6.02 x 1023 molecules9. (NH4)2CO3 2N = 28.0 8H = 8.0 C = 12.03O = 48.0 96.0 g/mol10. moles in 59.95 g CoCl2Co = 58.9 59.95 g/129.9g/mol = 0.46 mol CoCl22 Cl= 71.0 129.9g/mol11. grams in 0.42 mol Fe2O3 2 Fe = 111.6 (0.42 mol)(159.6g/mol) = 67.03 g Fe2O33 O = 48.0 159.6 g/mol

  25. 12. 6 molx Al(NO3)3 + 3 NaOH Al(OH)3 + 3 NaNO36 = x 3 1 3x = 6 x = 2 mol Al(OH)313. Al = 27.0 3 O = 48.0 (2 mol)(78.0g/mol) = 156 g Al(OH)33 H = 3.0 78.0 g/mol14. PV = nRT V = nRT/P(2.5mol)(0.082)(298 K)/0.895 atm=68.26 L15.H = Hfm H = (335 j/g)(543 g) = 181,905 joules16. H = mcDT H = (382 g)(4.18)(80 – 20 oC) = 95,805.6 joules17. 1. Boyle’s b car piston compresses fuel 2. Charles a. balloon heated – expands 3. P – T c. sun shines on car tire18.BaCl2 Na2CrO4HCl19 Sulfuric acid, Magnesium iodide, Potassium hydroxide20.(NH4)2CO3  2 NH4+1 + CO3-221. 3 Mg+2 + 2 PO4-3  Mg3(PO4)2 (s)

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