SOLVED

11) A sample of copper absorbs 43.6 kJ of heat, resulting in a temperature rise of 75.0°C, determine the mass (in kg) of the copper sample if the specific heat capacity of copper is 0.385 J/g°C. A) 1.51 kg B) 6.62 kg C) 1.26 kg D) 7.94 kg E) 3.64 kg 12) Determine the final temperature of a gold nugget (mass = 376 g) that starts at 398 K and loses 4.85 kJ of heat to a snowbank when it is lost. The specific heat capacity of gold is 0.128 J/g°C. A) 133 K B) 398 K C) 187 K D) 297 K E) 377 K 13) Calculate the change in internal energy (ΔE) for a system that is giving off 25.0 kJ of heat and is changing from 12.00 L to 6.00 L in volume at 1.50 atm pressure. (Remember that 101.3 J = 1 L?atm) A) +25.9 kJ B) -16.0 kJ C) -25.9 kJ D) -24.1 kJ E) 937 kJ 14) Calculate the change in internal energy (ΔE) for a system that is giving off 25.0 kJ of heat and is changing from 18.00 L to 15.00 L in volume at 1.50 atm pressure. (Remember that 101.3 J = 1 L?atm) A) +25.5 kJ B) -16.0 kJ C) -25.5 kJ D) -24.5 kJ E) 456 kJ 15) A 6.55 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in a bomb calorimeter. If the temperature rose by 32.9°C, use the information below to determine the heat capacity 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) 97.3 kJ/°C B) 38.9 kJ/°C C) 5.94 kJ/°C D) 6.84 kJ/°C E) 12.8 kJ/°C 16) A 21.8 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter, according to the following reaction. If the temperature rises from 25.0 to 62.3°C, determine the heat capacity of the calorimeter. The molar mass of ethanol is 46.07 g/mol. C2H5OH(l) + 3 O2(g) → 2 CO2(g) + 3 H2O(g)ΔH°rxn = -1235 kJ A) 4.99 kJ/°C B) 5.65 kJ/°C C) 63.7 kJ/°C D) 33.1 kJ/°C E) 15.7 kJ/°C 17) A 4.98 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in a bomb calorimeter with a heat capacity of 4.25 kJ/°C. If the temperature rose from 29.5°C to 69.8°C, determine the value of ΔH°comb for aniline. A) +7.81 × 103 kJ/mol B) -3.20 × 103 kJ/mol C) +1.71 × 103 kJ/mol D) -1.71 × 103 kJ/mol E) -7.81 × 103 kJ/mol 18) The temperature rises from 25.00°C to 29.00°C in a bomb calorimeter when 3.50 g of sucrose undergoes combustion in a bomb calorimeter. Calculate ΔErxn for the combustion of sucrose in kJ/mol sucrose. The heat capacity of the calorimeter is 4.90 kJ/°C. The molar mass of sugar is 342.3 g/mol. A) – 1.92 × 103 kJ/mole B) 1.92 × 103 kJ/mole C) – 1.23 × 103 kJ/mole D) 2.35 × 104 kJ/mole 19) A 12.8 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter with a heat capacity of 5.65 kJ/°C. Using the information below, determine the final temperature of the calorimeter if the initial temperature is 25.0°C. The molar mass of ethanol is 46.07 g/mol. C2H5OH(l) + 3 O2(g) → 2 CO2(g) + 3 H2O(g)ΔH°rxn = -1235 kJ A) 53.4°C B) 28.1°C C) 111°C D) 85.7°C E) 74.2°C 20) A 35.6 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter, according to the following reaction. If the temperature rose from 35.0 to 76.0°C and the heat capacity of the calorimeter is 23.3 kJ/°C, what is the value of DH°rxn? The molar mass of ethanol is 46.07 g/mol. C2H5OH(l) + 3 O2(g) → 2 CO2(g) + 3 H2O(g)ΔH°rxn = ? A) -1.24 × 103 kJ/mol B) +1.24 × 103 kJ/mol C) -8.09 × 103 kJ/mol D) -9.55 × 103 kJ/mol E) +9.55 × 103 kJ/mol