Category: Medium Section: 6.692.The heat of solution of calcium chloride CaCl2is –82.8 kJ/mol, and the combined heats of hydration of 1.00 mole of gaseous calcium ions and 2.00 mole of gaseous chloride ionsis –2327 kJ. What is the lattice energy of calcium chloride?Category: Medium Section: 6.793.The heat of solution of NH4NO3is 26.2 kJ/mol. Is heat evolved or absorbed when a solution of NH4NO3is diluted by addition of more water?Category: Easy Section: 6.794.A 26.2 g piece of copper metal is heated from 21.5°C to 201.6°C. Calculate the amount of heat absorbed by the metal. The specific heat of Cu is 0.385 J/g·°C.Category: Medium Section: 6.595.A 0.1946 g piece of magnesium metal is burned in a constant-volume calorimeter that hasa heat capacity of 1349 J/°C. The calorimeter contains 500. g of water and the temperature rise is 1.40°C. Calculate the heat of combustion of magnesium metal in kJ/g,given that the specific heat of water = 4.184 J/g·°C.Category: Medium Section: 6.5Page 135
Chapter 6: Thermochemistry96.A 0.3423 g sample of pentane, C5H12, was burned in a bomb calorimeter. The temperature of the calorimeter and the 1.000 kg of water contained therein rose from 20.22°C to 22.82°C. The heat capacity of the calorimeter is 2.21 kJ/°C. The heat capacity of water = 4.184 J/g·°C. How much heat was given off during combustion of the sample of pentane?Category: Medium Section: 6.597.A 0.3423 g sample of pentane, C5H12, was burned in a bomb calorimeter. The temperature of the calorimeter and the 1.000 kg of water contained therein rose from 20.22°C to 22.82°C. The heat capacity of the calorimeter is 2.21 kJ/°C. The heat capacity of water = 4.184 J/g·°C. What is the heat of combustion, in kilojoules, per gram of pentane?Category: Medium Section: 6.598.The heat of combustion of propane, C3H8, 2220 kJ/mol. The specific heat of copper is 0.385 J/g°C. How many grams of propane must be burned to raise the temperature of a 10.0 kg block of copper from 25.0°C to 65.0°C, assuming none of the heat is lost to the surroundingsAns:3.06 gCategory: Medium Section: 6.599.The residential rate for natural gas is about $15 per thousand cubic foot. Burning one cubic foot of natural gas releases about 1080 kJ of heat. How much would it cost to heat the water in a 25,000 gallon swimming pool from 52°F to 78°F, assuming all of the heat from burning the natural gas went towards warming the water? (1 gal = 3.785 L; the specific heat of water = 4.184 J/g·°C)Category: Difficult Section: 6.5100.The heat of neutralization of HCl by NaOH is H°rxn= –56.2 kJ/mol. How much heat is released when 125 mL of 1.750 M HCl is mixed with 195 mL of 0.667 M NaOH?Category: Difficult Section: 6.4101.The heat released when one mole of water is formed from the elements is 1,198 kJ. An experiment was conducted that permitted water to form in this manner, and the heat was contained in 2.0 liters of water. The water temperature before the reaction was 34.5°C, and after the reaction it had risen to 52.0°C. How many moles of water were formed? (The specific heat of water is 4.184 J/g·°C.)Category: Medium Section: 6.5Page 136
Chapter 6: Thermochemistry102.When an automobile engine starts, the metal parts immediately begin to absorb heat released during the combustion of gasoline. How much heat will be absorbed by a 165 kg iron engine block as the temperature rises from 15.7°C to 95.7°C? (The specific heat
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