Module 6 Unit 2 Assignment C

MODULE 6 UNIT 2 new Assignment Part C By: Connie Warburton Show all calculations. 1. Phosphorous burns in air to produce dense white clouds of P 4 O 10 gas. When this gas is dissolved in rain water, phosphoric acid, H 3 PO 4 , is produced. How much energy is released when 14.2 g of P 4 O 10 reacts? (3 marks) P 4 O 10 (g) + 6H 2 O (l)  4H 3 PO 4 (aq) + 424 kJ 1 mol P 4 O 10 = ( 4 x 30.974g) + (10 x 16.00g) = 283.896 g 14.2 g x 1 mol / 283.896 g = 0.0500183166 = 0.05 mol P 4 O 10 0.05 mol P 4 O 10 x 424 kJ / 1 mol = 21.2 kJ P 4 O 10 2. How much heat is absorbed during photosynthesis when 9.22 grams of glucose C 6 H 12 O 6 is produced? (3 marks) 6CO 2 + 6H 2 O + 2803 kJ  C 6 H 12 O 6 + 6O 2 1 mol C 6 H 12 O 6 = (6 x 12.011g) + (12 x 1.008g) + (6 x 16.00g) = 180.162 g 9.22 g C 6 H 12 O 6 x 1 mol / 180.162 g = 0.0511761637 = 0.0512 mol C 6 H 12 O 6 0.0512 mol C 6 H 12 O 6 x 2803 kJ / 1 mol = 143.5136 = 1.44 x 10 2 kJ 3. When propane (C 3 H 8 ) is burned in oxygen gas (O 2 ), it forms carbon dioxide and water while releasing 2220 kJ/mol of heat energy. C 3 H 8 + 5O 2  3CO 2 + 4H 2 O + 2220 kJ How much energy will be released when 55 L of propane is burned at STP? (3 marks) 1 mol = 22.4 L 55 L C 3 H 8 x 1 mol / 22.4 L = 33.7053571429 = 33.71 mol C 3 H 8 33.71 mol C 3 H 8 x 2220 kJ / 1 mol = 74836.2 = 7.5 x 10 4 kJ How much energy will be released when 30 L of propate is burned at 20°C and 99.5 kPa? (3 marks) Vf = 30 L C 3 H 8 x 273 K / 293 K x 99.5 kPa / 101 kPa = 27.5370864732 = 27.54 L C 3 H 8 27.53 L C 3 H 8 x 1 mol / 22.4 L = 1.2294642857 = 1.23 mol C 3 H 8 1.23 mol C 3 H 8 x 2220 kJ / 1 mol = 2730.6 = 2.7 x 10 3 kJ 1

Total: 12 marks Submission Instructions Submit your assignment using the drop box on the Assignment page for this unit. Remember to include references. 2