PRACTICE MINI EXAM 1 The exam will cover material from the chapter on Thermochemistry homework worksheets and any other topic covered during class and discussion The questions in this practice exam are of similar difficulty to those in the actual exam however the questions will not be the same Do not memorize the questions I 1 Based on the following thermochemical equations what is the heat of vaporization of Multiple choice titanium IV chloride A 41 0 kJ mol B 1567 4 kJ mol Ti s 2 Cl2 g TiCl4 l TiCl4 g 2 Cl2 g Ti s H 804 2 kJ mol H 763 2 kJ mol C 1567kJ mol D 41 0 kJ mol E 763 7 kJ mol 2 What is H rxn for the following reaction SiO2 s 4HCl g SiCl4 g 2H2O g Substance SiO2 s SiCl4 g HCl g H2O g H f kJ mol 859 3 662 8 92 3 241 8 C 47 0 kJ mol D 82 1 kJ mol E 530 6 kJ mol A 1856 2 kJ mol B 1372 6 kJ mol 4 184 J g C A 2 60 J B 2 63 kJ 3 What is q if 28 6 g of water is heated from 22 0 C to 78 3 C The specific heat of water is C 6 74 kJ D 9 37 kJ E 3 94 104kJ 4 Given H 90 25 kJ for the reaction NO g N2 g O2 g calculate H for the reaction N2 g O2 g 2 NO g C 90 25 kJ D 180 50 kJ E NA A 180 50 kJ B 90 25 kJ 5 Calculate the quantity of heat released when 4 00 g of CH4 g are burned in excess oxygen according to the reaction CH4 g 2 O2 g CO2 g 2 H2O g H0 B 401 1 kJ C 200 6 kJ rxn 802 2 kJ D 100 3 kJ A 802 2 kJ 6 Which statement is correct A H is a measure of heat absorbed or released by the system for a process carried out at E 802 2kJ B According to sign convention a positive q signifies that heat flows from the system to the C The standard enthalpy of formation of C diamond at 25 C and 1 atm is zero D The standard enthalpy of formation of CH4 g is not the same as the standard enthalpy of constant volume surroundings combustion of CH4 g E All are correct 7 At 25 C the same quantity of heat is added to 1 00 g samples of gold and iron Identify the correct statement Metal Gold Iron Specific Heat Capacity J g 1 C 1 0 128 0 451 A The temperatures of both will remain the same B The temperatures of both will increase by the same amount C The temperatures of both will decrease by the same amount D The temperature of the gold sample will rise higher than that of iron E The temperature of the iron sample will rise higher than that of gold II 8 The formation of a bond is an endothermic process 9 A reaction is expected to be exothermic if the bonds of the products are stronger than True False those of the reactants Short answer 10 The bond energy of a double bond is exactly twice that of a single bond III 11 15 points The enthalpy of combustion of benzoic acid C6H5COOH is commonly used as the standard for calibrating a bomb calorimeter Its value is accurately known to be 3226 7 kJ mol When 1 9862 g of benzoic acid are burned in a bomb calorimeter the temperature rises from 21 84 C to 25 67 C Determine the heat capacity of the bomb assuming it is surrounded by exactly 2 000 kg of water 12 10 points From the following determine the enthalpy change when 50 0 g of CO is burned completely in oxygen CO g O2 g CO2 g CO2 393 3 kJ mol CO 110 5 kJ mol 13 15 points Calculate the standard molar enthalpy of formation of NO g from the following data 14 10 points When a molecule can form two different structures the structure with the stronger bonds is usually the more stable form Use bond energies to predict the correct structure of the hydroxylamine molecule 15 20 points Glyceryl trioleate a typical fat is metabolized by the body by the following reaction 2C57H104O6 s 16O2 g 114CO2 g 104H2O l H 6 70 x 104 kJ a How much heat energy must be expelled by the body to rid the body of 0 5 pounds of b If a swimmer burns off 2000 kJ for each 100 laps he swims how much fat will she burn fat 1lb 453 6 g off in pounds if he swims 15 laps 22229822298N 2O 2NO 66 4 kJ2NO O 2NO 114 1 kJgggHgggH Equations and Data Sheet qp H q m c T q C T H H H PV nRT Ptotal iPi 2 2 3 1 2 2 1 1 atm 101325 Pa 760 mmHg 760 Torr 14 7 psi K C 273 15 Pressure units 1 bar 1 X 105 Pa R units R 8 31 J mol K 8 31 m3 Pa mol K 0 08206 L atm mol K Answer Key PRACTICE MINI EXAM 1 1 A 2 D 3 C 4 D 5 C 6 D 7 D 8 F 9 T 10 F 11 C 5 28 KJ C 12 505kJ 13 90 25kJ 14 First structure 15 a 8 58 x 103 kJ b 0 0175 lb