Chapter 3 Question 1 Convert the following energy units a 5 60 102 kJ to J b 2850 kcal to kJ c 5 85 106 J to kcal Question 2 At constant pressure which of these systems do work on the surroundings Check all that apply 2A g B g C g A g B g 3C g A s B g 2C g A g B g C g Question 3 How much work must be done on a system to decrease its volume from 11 0 L to 4 0 L by exerting a constant pressure of 4 0 atm Question 4 Consider an ideal gas enclosed in a 1 00 L container at an internal pressure of 10 0 atm Calculate the work w if the gas expands against a constant external pressure of 1 00 atm to a final volume of 15 0 L Now calculate the work done if this process is carried out in two steps 1 First let the gas expand against a constant external pressure of 5 00 atm to a volume of 3 00 L 2 From there let the gas expand to 15 0 L against a constant external pressure of 1 00 atm Question 5 If a system has 275 kcal of work done to it and releases 5 00 102 kJ of heat into its surroundings what is the change in internal energy of the system Question 6 Classify each of the following as a path function or a state function heat energy enthalpy work distance traveled Question 7 The specific heat of a certain type of cooking oil is 1 75 J g C How much heat energy is needed to raise the temperature of 2 03 kg of this oil from 23 C to 191 C Question 8 A 57 89 g sample of a substance is initially at 28 4 C After absorbing 1769 J of heat the temperature of the substance is 173 0 C What is the specific heat c of the substance Question 9 The specific heat of a certain type of metal is 0 128 J g C What is the final temperature if 305 J of heat is added to 89 1 g of this metal initially at 20 0 C Question 10 An 80 0 gram sample of a gas was heated from 25 C to 225 C During this process 346 J of work was done by the system and its internal energy increased by 8795 J What is the specific heat of the gas Question 11 When 1752 J of heat energy is added to 37 4 g of ethanol C2H6O the temperature increases by 19 1 C Calculate the molar heat capacity of C2H6O Question 12 Consider the following reaction The formation of 75 0 g of Fe results in the release of 15500 kJ of heat the absorption of 1110 kJ of heat the absorption of 15500 kJ of heat the absorption of 277 kJ of heat the release of 277 kJ of heat the release of 1110 kJ of heat Question 13 Using the standard enthalpies of formation what is the standard enthalpy of reaction Question 14 Given that calculate the value of H rxn for Question 15 The 1995 Nobel Prize in Chemistry was shared by Paul Crutzen F Sherwood Rowland and Mario Molina for their work concerning the formation and decomposition of ozone in the stratosphere Rowland and Molina hypothesized that chlorofluorocarbons CFCs in the stratosphere break down upon exposure to UV radiation producing chlorine atoms Chlorine was previously identified as a catalyst in the breakdown of ozone into oxygen gas Using the enthalpy of reaction for two reactions with ozone determine the enthalpy of reaction for the reaction of chlorine with ozone Question 16 Use the molar bond enthalpy data in the table to estimate the value of H rxn for the equation The bonding in the molecules is shown here Question 17 Skipped Question 18 When a 4 00 g sample of RbBr is dissolved in water in a calorimeter that has a total heat capacity of 1 471 kJ K 1 the temperature decreases by 0 360 K Calculate the molar heat of solution of RbBr Question 19 In a constant pressure calorimeter 50 0 mL of 0 310 M Ba OH 2 was added to 50 0 mL of 0 620 M HCl The reaction caused the temperature of the solution to rise from 24 02 C to 28 24 C If the solution has the same density and specific heat as water what is H for this reaction per mole of H2O produced Assume that the total volume is the sum of the individual volumes Question 20 When methanol CH3OH is burned in the presence of oxygen gas O2 a large amount of heat energy is released For this reason it is often used as a fuel in high performance racing cars The combustion of methanol has the following balanced thermochemical equation How much methanol in grams must be burned to produce 753 kJ of heat