1 How much heat must be removed from 250 0 mL of water to lower its temperature from 80 C to 25 C dwater 1 00 g ml swater 4 18 J g C CH 201 Self Study Worksheet 3 Key q ms T 250 0 mL 1 00 g mL 4 18 J g C 25 80 C 1 kJ 1000 J 57 48 kJ removed 2 When glucose combines with O2 the following reaction occurs C6H12O6 s 6 O2 g 6 CO2 g 6 H2O l H 2820 kJ a How many grams of glucose would have to be burned to heat 1 000 kg of water from 25 00 to 30 00 C swater 4 18 J g C q to heat water ms T 1000 g 4 18 J g C 5 C 20 9 kJ 20 9 kJ mole glucose 180 g glucose 1 33 grams glucose 2820 kJ released mole b How much energy can be obtained from the oxidation of 1 00 g of glucose 1 00 g glucose mol 180 g glucose mol glucose 2820 kJ 15 7 kJ 15 7 kJ energy obtained by surroundings 3 a What mass of ice is needed to chill 50 00 mL of 25 0 C water to 0 C For water Hfusion 6 01 kJ mol density 1 00 g mL specific heat 4 18 J g C q released by water ms T 50 00 mL 1 00 g mL 4 18 J g C 25 C 5 225 kJ qreleased by water qabsorbed by ice 5 225 kJ mol ice 18 g ice 15 6 g ice 6 01 mol ice J b What would be the final temperature of a solution made with 25 00 mL of 0 C water and 125 mL of 80 C water heat absorbed by 0 water heat released by 80 water or q0 q80 ms T 25 00 mL 1 00 g mL 4 18 J g C Tf 0 C 125 mL 1 00 g mL 4 18 J g C Tf 80 C 25 g Tf 125 g Tf 80 C 1 20Tf 80 C Tf 66 7 C Also you can reason through this one for every 1 hot water that cools down 1 C 5 cold waters will heat up 1 C So 1 6 of 80 C 13 3 C and Tf 80 13 3 C 66 7 C CH 201 Self Study Worksheet 3 Key 4 a Given Na s Cl2 g Na g Cl g Na g Cl g Na g Cl g Na s Cl2 g NaCl s Calculate H for the following reaction H1 230 kJ H2 147 kJ H3 441 kJ Na g Cl g NaCl s H Na s Cl2 g NaCl s H3 Na g Cl g Na s Cl2 g flipped H1 Na g Cl g Na g Cl g flipped H2 Na g Cl g NaCl s H H3 H1 H2 441 230 147 kJ 818 kJ b How much heat is absorbed evolved in the production of 20 00 g of NaCl s 818 kJ mol NaCl 58 4 g NaCl mol NaCl 20 g NaCl 280 1 kJ means evolved 5 Nickel tetracarbonyl Ni CO 4 decomposes upon heating according to the following reaction Ni CO 4 g Ni s 4 CO g H 160 7 kJ Calculate H q w and E when 0 784 moles of Ni CO 4 decomposes at 1 atm and 30 0 C R 0 08206 Latm molK 8 314 J molK K C 273 Const P H q 160 7 kJ mol 0 784 mol 126 0 kJ ng so work is done BY the system indicating a negative work w ngRT 3 mols mol Ni CO 4 0 784 mol Ni CO 4 8 314 J molK 303 K 5 93 kJ E q w 126 0 kJ 5 93 kJ 120 1 kJ 6 Calculate H for the reaction below from the Hf s given below 3H2O l 2CO2 g C2H5OH l 3O2 g 285 83 393 51 277 7 0 kJ mol Hf H Hf C2H5OH l 3 Hf O2 g 3 Hf H2O l 2 Hf CO2 g 277 7 3 0 3 285 83 2 393 51 1367 kJ 7 Using bond dissociation energies listed below calculate H for the reaction of methane with chlorine and fluorine to give Freon 12 CF2Cl2 CH4 g 2Cl2 g 2F2 g CF2Cl2 g 2HF g 2HCl g Bond Dissociation Energies KJ mol Bonds broken Bonds formed C H 413 C F 485 C Cl 339 Cl Cl 239 F F 154 H Cl 427 H F 565 4 C H 2 Cl Cl 2 F F 2 C F 2 C Cl 2 H F 2 H Cl 4 413 2 239 2 154 2 485 2 339 2 565 2 427 1652 478 308 970 678 1130 854 2438 3632 1194 KJ
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