56) Using the following thermochemical equation, determine the amount of heat produced per kg of CO2formed during the combustion of benzene (C6H6). 2 C6H6(l) + 15 O2(g) →12 CO2(g) + 6 H2O(g) ΔH°rxn = -6278 kJ A) 1.43×105kJ/kg CO2 B) 2.30×104kJ/kg CO2 C) 4.34×104kJ/kg CO2

D) 1.19 ×104kJ/kg CO2 E) 8.40×105kJ/kg CO2 56) According to the following thermochemical equation, what mass of HF (in g) must react in order to produce 345 kJ of energy? Assume excess SiO2. SiO2(s) + 4 HF(g) →SiF4(g) + 2 H2O(l) ΔH°rxn = -184 kJ 57) What volume of benzene (C6H6, d= 0.88 g/mL, molar mass = 78.11 g/mol) is required to produce 1.5 ×103kJ of heat according to the following reaction? 2 C6H6(l) + 15 O2(g) →12 CO2(g) + 6 H2O(g) ΔH°rxn = -6278 kJ 58) Which of the following statements is true? 59) A piece of iron (mass = 25.0 g) at 398 K is placed in a styrofoam coffee cup containing 25.0 mL of water at 298 K. Assuming that no heat is lost to the cup or the surroundings, what will the final temperature of the water be? The specific heat capacity of iron = 0.449 J/g°C and water = 4.18 J/g°C. A) 348 K B) 308 K C) 287 K D) 325 K E) 388 K

60) A 100.0 mL sample of 0.300 M NaOH is mixed with a 100.0 mL sample of 0.300 M HNO3in a coffee cup calorimeter. If both solutions were initially at 35.00°C and the temperature of the resulting solution was recorded as 37.00°C, determine the ΔH°rxn(in units of kJ/mol NaOH) for the neutralization reaction between aqueous NaOH and HCl. Assume 1) that no heat is lost to the calorimeter or the surroundings, and 2) that the density and the heat capacity of the resulting solution are the same as water. 61) Use the standard reaction enthalpies given below to determine ΔH°rxnfor the following reaction P4(g) + 10 Cl2(g) →4PCl5(s) ΔH°rxn = ? Given: PCl5(s) →PCl3(g) + Cl2(g) ΔH°rxn = +157 kJ P4(g) + 6 Cl2(g) →4 PCl3(g) ΔH°rxn= -1207 kJ

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- Fall '08
- LEMASTER
- Chemistry, Thermodynamics, Mole, Energy, Heat, Chemical reaction