SOLVED

21) A 6.55 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in a bomb calorimeter with a heat capacity of 14.25 kJ/°C. If the initial temperature was 32.9°C, use the information below to determine the value of the final temperature of the calorimeter. 4 C6H5NH2(l) + 35 O2(g) → 24 CO2(g) + 14 H2O(g) + 4 NO2(g) ΔH°rxn = -1.28 × 104 kJ A) 257°C B) 46.6°C C) 48.7°C D) 41.9°C E) 931°C 22) Which statement is false? A) An exothermic reaction gives heat off heat to the surroundings. B) Enthalpy is the sum of a system’s internal energy and the product of pressure and volume change. C) ΔErxn is a measure of heat. D) ΔHrxn is the heat of reaction. E) Endothermic has a positive ΔH. 23) Given w = 0, an endothermic reaction has the following. A) +ΔH and -ΔE B) – ΔH and +ΔE C) + ΔH and +ΔE D) – ΔH and -ΔE 24) How much energy is required to decompose 765 g of PCl3, according to the reaction below? The molar mass of PCl3 is 137.32 g/mol and may be useful. 4 PCl3(g) → P4(s) + 6 Cl2(g)ΔH°rxn = +1207 kJ A) 2.31 × 103 kJ B) 4.33 × 103 kJ C) 6.72 × 103 kJ D) 1.68 × 103 kJ E) 5.95 × 103 kJ 25) How much energy is required to decompose 612 g of PCl3, according to the reaction below? The molar mass of PCl3 is 137.32 g/mol and may be useful. 4 PCl3(g) → P4(s) + 6 Cl2(g)ΔH°rxn = +1207 kJ A) 1.85 × 103 kJ B) 3.46 × 103 kJ C) 5.38 × 103 kJ D) 1.34 × 103 kJ E) 4.76 × 103 kJ 26) How much energy is evolved during the formation of 98.7 g of Fe, according to the reaction below? Fe2O3(s) + 2 Al(s) → Al2O3(s) + 2 Fe(s)ΔH°rxn = -852 kJ A) 753 kJ B) 1.51 × 103 kJ C) 4.20 × 103 kJ D) 482 kJ E) 241 kJ 27) How much energy is evolved during the formation of 197 g of Fe, according to the reaction below? Fe2O3(s) + 2 Al(s) → Al2O3(s) + 2 Fe(s)ΔH°rxn = -852 kJ A) 1.52 × 103 kJ B) 3.02 × 103 kJ C) 8.40 × 103 kJ D) 964 kJ E) 482 kJ 28) Using the following thermochemical equation, determine the amount of heat produced per kg of CO2 formed during the combustion of benzene (C6H6). 2 C6H6(l) + 15 O2(g) → 12 CO2(g) + 6 H2O(g)ΔH°rxn = -6278 kJ A) 1.43 × 105 kJ/kg CO2 B) 2.30 × 104 kJ/kg CO2 C) 4.34 × 104 kJ/kg CO2 D) 1.19 × 104 kJ/kg CO2 E) 8.40 × 105 kJ/kg CO2 29) Using the following equation for the combustion of octane, calculate the amount of moles of carbon dioxide formed from 100.0 g of octane. The molar mass of octane is 114.33 g/mole. The molar mass of carbon dioxide is 44.0095 g/mole. 2 C8H18 + 25 O2 → 16 CO2 + 18 H2OΔH°rxn = -11018 kJ A) 18.18 moles B) 6.997 moles C) 14.00 moles D) 8.000 moles E) 10.93 moles 30) Using the following equation for the combustion of octane, calculate the amount of moles of oxygen that reacts with 100.0 g of octane. The molar mass of octane is 114.33 g/mole. The molar mass of carbon dioxide is 44.0095 g/mole. 2 C8H18 + 25 O2 → 16 CO2 + 18 H2OΔH°rxn = -11018 kJ A) 18.18 moles B) 6.997 moles C) 14.00 moles D) 8.000 moles E) 10.93 moles