Question

Homework Thermochemistry Name: 1. Calculate the mass of O that is produced by photosynthesis when 2.49 x 109 kJ of solar energy is consumed by the following reaction: 6 H20 (1) + 6 CO2 (g) - C&H 20(s) + 6 02 (g) ; AH-2803 kJ 2. Given the following thermochemical equation, what amount of energy is absorbed/given off when 255 g of CuO is reacted. 2 Cu20 (s) - 4 Cu (s) + O2(g) : AH = 333.8 kJ 3. Is the reaction in question (2) exothermic or endothermic? 4. Classify each of the following processes as exothermic or endothermic a) ice melting b) a sparkler burning c) acetone evaporating from skin 5. Ethanol, C2H5OH, is mixed with gasoline and sold as gasohol. Use the following to calculate the grams of ethanol needed to provide 342 kJ of heat. CH-OH () + 3 02 (g) → 2 CO2(g) + 3 H20 (g); AH = -1235 kJ 6. Calcium oxide (Cao) reacts with water to produce calcium hydroxide. The heat released by this reaction is sufficient to ignite paper. How much heat is released when 72.1 g of calcium oxide reacts? CaO (8) + H20 (1) ► Ca(OH)2 (s); AH = -65.2 kJ

Answer 1

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192 gram DATE mol O2 = 32 gram. 6 mol O2 = 6x32 = DATE DOTD According to Reaction 2030 kJ Consumed for the production of = 6 mol O2 (192gram) 1 Kg Consumed = 192 gram Production of oz 2.49 %10 kJ Consumed = 192x2.49 810 gram on 1689.32 gram O2 moler muss of Cago = 143.09 g/mol 2x 143.09 = 206.18 2030 V Now 2830 2. 206 18 grom Cuzo absorbed = 333. & KJ 1 grom Cu2o absorbed - 333.8 kJ 286.10 255 gram Cuzo absorted = 333.0 x 255 kJ 286.18 = 299.43 k Reaction (2) is Endothermic Reaction Because An= tue Cheat absorbed). (3) I (4. @ ice melting Energy absorbed & Endothermic 6 a Sparkler burning - Exothermic ① acetone evaporating from Skin = Endothermic 105 GHon molar mass = 12x2+6+ 16 = 84+ 22 =46 • 46 grom Canson provided = 1235 kJ PAGE

DATE 1235 DATE DD 1235 kJ Provided by = 46 grom Ethanol I ks " - 46 gram Ethanol 342 KJ Rovided by = 46 X 342 gram 1235 a 12.74 gram) Ans 1 (6) According to Reaction I mol Gao Produced = 65.2 KI (Imol = 40 + 16 = 56 gram) 56 grom Cao Produce = 65.2KJ 1 gram Cao Produce = 65.2 kJ 72.1 gram Cao Produce - 65.2 x 72.1 kJ E83.945 kJ) 56 56 Thank Hope this will help you