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Unit 5 Whiteboard Review

Unit 5 Whiteboard Review. Identify the fuel in this combustion reaction: H 2 + O 2  H 2 O. Hydrogen!. When the system releases energy to its surroundings, the process is __________. Exothermic!. Balance the following combustion equation: C 5 H 12 + O 2  H 2 O + CO 2.

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Unit 5 Whiteboard Review

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  1. Unit 5 Whiteboard Review

  2. Identify the fuel in this combustion reaction:H2 + O2 H2O Hydrogen!

  3. When the system releases energy to its surroundings, the process is __________. Exothermic!

  4. Balance the following combustion equation:C5H12 + O2 H2O + CO2 C5H12 + 8O26H2O + 5CO2

  5. The heat of fusion for iron is 13.8 kJ/mol and the heat of fusion for lead is 4.8 kJ/mol. If you have 2 moles of both iron and lead, which one will take less time to melt if they are sharing a heat source? Lead!

  6. You burn 2.8 grams of ethanol (C2H5OH) and find that it raises the temperature of 260 grams of water (specific heat 4.18 J/g°C) from 22°C to 47°C. What is the heat of combustion of ethanol (in kJ/mol)? 2.8 g = 0.061 mol 46 g/mol Q = mCΔT = (260g)(4.18 J/g°C)(47-22) = 27170 J Heat of combustion = 27.17 kJ = 445.41 kJ/mol 0.061 mol

  7. What are the particles doing during “A”? Moving faster (kinetic energy increases)!

  8. Which of the following 3 molecules would release the most energy per mole of fuel combusted?C4H10 or CH4 or C4H10O C4H10

  9. What equation would you use to determine the energy transformation occurring at letter "D"? Qvap = ΔHvap x mol!

  10. Which letter represents the heat of reaction for this reaction? B A C

  11. 7. Which letter represents a period of time in which bonds are breaking? B A C

  12. What are the particles doing during “D”? Moving further apart (potential energy increases)!

  13. 8. What kind of reaction is this? (Endothermic or exothermic) B A C

  14. 9. In reaction A, the activation energy needed is 250 kJ/mol and the heat of reaction is +60 kJ/mol. Draw the energy diagram for Reaction A. Is the reaction endothermic or exothermic? ENDOTHERMIC 250 kJ/mol 60 kJ/mol

  15. The heat of reaction for the combustion of butane (C4H10) is -2887 kJ/mol. The activation energy needed for this reaction is 3514 kJ/mol. Draw an energy diagram showing what happens to energy during this reaction. How much energy is required for breaking bonds? How much energy is released for making bonds?

  16. Use the table below to calculate the total energy required to break all the bonds in 1 mole of hexanol(C6H14O). 13 C-H, 5 C-C, 1 C-O, 1 O-H 13(99) + 5(83) + 86 + 112 = 1900 cal/mol

  17. Write a balanced equation for the combustion of butane: C4H10. • What is the heat of reaction? • Is this reaction endothermic or exothermic?

  18. Write a balanced equation for the combustion of butane: C4H10. 2 C4H10 + 13 O2 8 CO2 + 10 H2O 6 C-C (6 x 83) + 20 C-H (20 x 99) + 13 O=O (13 x 118) = 4012 Cal/mol needed to BREAK bonds. 16 C=O (16 x 191) + 20 O-H (20 x 112) = 5296 Cal/mol produced when bonds are MADE. 4012 – 5296 = -1284 Cal/mol

  19. You burn 5.0 grams of ethanol (C2H5OH) and find that it raises the temperature of 100 grams of water (specific heat 4.18 J/g°C) from 20°C to 40°C. What is the heat of combustion of ethanol (kJ/mol)? 5.0 g = 0.109 mol 46 g/mol Q = mCΔT = (100g)(4.18 J/g°C)(40-20) = 8360 J Heat of combustion = 8.360 kJ = 76.7 kJ/mol 0.109 mol

  20. Which of the following 3 molecules would release the most energy per mole of fuel combusted? C5H12O OR C5H12 or C4H10 C5H12

  21. In reaction A, the activation energy needed is 300 kJ/mol and the heat of reaction is -60 kJ/mol. Draw the energy diagram for Reaction A. Is the reaction endothermic or exothermic? EXOTHERMIC

  22. Use the table below to calculate the total energy required to break all the bonds in 1 mole of propane (C3H8). 8(99) + 2(83) = 958 kJ/mol

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