Chemistry: A Molecular Approach, 2e (Tro)Chapter 6 ThermochemistryMultiple Choice Questions1) Energy that is associated with the position or composition of an object is calledA) kinetic energyB) thermal energyC) potential energyD) chemical energyAnswer: CDiff: 1 Page Ref: 6.22) Which of the following signs on q and w represent a system that is doing work on thesurroundings, as well as losing heat to the surroundings?A) q = - , w = -B) q = +, w = +C) q = -, w = +D) q = +, w = -E) None of these represent the system referenced above.Answer: ADiff: 1 Page Ref: 6.33) Which of the following signs on q and w represent a system that is doing work on thesurroundings, as well as gaining heat from the surroundings?A) q = +, w = -B) q = -, w = +C) q = +, w = +D) q = -, w = -E) None of these represent the system referenced above.Answer: ADiff: 1 Page Ref: 6.34) Which of the following is TRUE if Esys = - 95 J?A) The system is gaining 95 J, while the surroundings are losing 95 J.B) The system is losing 95 J, while the surroundings are gaining 95 J.C) Both the system and the surroundings are gaining 95 J.D) Both the system and the surroundings are losing 95 J.E) None of the above are true.Answer: BDiff: 1 Page Ref: 6.31Copyright (c) 2011 Pearson Education, Inc.

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5) Calculate the change internal energy (E) for a system that is giving off 45.0 kJ of heat and isperforming 855 J of work on the surroundings.A) 44.1 kJB) -44.1 kJC) -45.9 kJD) 9.00 x 102 kJE) -9.00 x 102 kJAnswer: CDiff: 1 Page Ref: 6.36) For Esys to always be -, what must be true?A) q = wB) +q > -wC) +w > -qD) -w > +qAnswer: DDiff: 2 Page Ref: 6.37) Define heat capacity.A) the quantity of heat required to raise the temperature of 1 mole of a substance by 1CB) the quantity of heat required to change a system's temperature by 1CC) the quantity of heat required to raise the temperature of 1 gram of a substance by 1CD) the quantity of heat required to raise the temperature of 1 g of a substance by 1FE) the quantity of heat required to raise the temperature of 1 liter of a substance by 1CAnswer: BDiff: 1 Page Ref: 6.48) Define specific heat capacity.A) the quantity of heat required to raise the temperature of 1 mole of a substance by 1CB) the quantity of heat required to change a system's temperature by 1CC) the quantity of heat required to raise the temperature of 1 gram of a substance by 1CD) the quantity of heat required to raise the temperature of 1 gram of a substance by 1FE) the quantity of heat required to raise the temperature of 1 liter of a substance by 1CAnswer: CDiff: 1 Page Ref: 6.49) Define molar heat capacity.A) the quantity of heat required to raise the temperature of 1 mole of a substance by 1CB) the quantity of heat required to change a system's temperature by 1CC) the quantity of heat required to raise the temperature of 1 gram of a substance by 1CD) the quantity of heat required to raise the temperature of 1 g of a substance by 1FE) the quantity of heat required to raise the temperature of 1 liter of a substance by 1CAnswer: ADiff: 1 Page Ref: 6.42Copyright (c) 2011 Pearson Education, Inc.

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10) Give the units of heat capacity.A) J/CB) J/g CC) J/mole CD) g/ CE) mol/ CAnswer: ADiff: 1 Page Ref: 6.411) Give the units of specific heat capacity.A) 1/CB) J/g CC) J/mole CD) g/ CE) mol/ CAnswer: BDiff: 1 Page Ref: 6.412) A piece of iron (C=0.449 J/gC) and a piece of gold (C=0.128 J/gC) have identical masses.If the iron has an initial temperature of 498 K and the gold has an initial temperature of 298 K,which of the following statements is TRUE of the outcome when the two metals are placed incontact with one another? Assume no heat is lost to the surroundings.A) Since the two metals have the same mass, the final temperature of the two metals will be 398K, exactly halfway between the two initial temperatures.B) Since the two metals have the same mass, but the specific heat capacity of gold is muchsmaller than that of iron, the final temperature of the two metals will be closer to 298 K than to498 K.C) Since the two metals have the same mass, the thermal energy contained in the iron and goldafter reaching thermal equilibrium will be the same.D) Since the two metals have the same mass, the thermal energy contained in each metal afterequilibrium will be the same.E) None of the above are true.Answer: DDiff: 1 Page Ref: 6.413) Which of the following substances (with specific heat capacity provided) would show thegreatest temperature change upon absorbing 100.0 J of heat?A) 10.0 g Ag, CAg = 0.235 J/gCB) 10.0 g H2O, CH2O = 4.18 J/gCC) 10.0 g ethanol, Cethanol = 2.42 J/gCD) 10.0 g Fe, CFe = 0.449 J/gCE) 10.0 g Au, CAu = 0.128 J/gCAnswer: EDiff: 2 Page Ref: 6.43Copyright (c) 2011 Pearson Education, Inc.

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14) Which of the following (with specific heat capacity provided) would show the smallesttemperature change upon gaining 200.0 J of heat?A) 50.0 g Al, CAl = 0.903 J/gCB) 50.0 g Cu, CCu = 0.385 J/gCC) 25.0 g granite, Cgranite = 0.79 J/gCD) 25.0 g Au, CAu = 0.128 J/gCE) 25.0 g Ag, CAg = 0.235 J/gCAnswer: ADiff: 2 Page Ref: 6.415) Calculate the amount of heat (in kJ) required to raise the temperature of a 79.0 g sample ofethanol from 298.0 K to 385.0 K. The specific heat capacity of ethanol is 2.42 J/gC.A) 57.0 kJB) 16.6 kJC) 73.6 kJD) 28.4 kJE) 12.9 kJAnswer: BDiff: 2 Page Ref: 6.416) Calculate the amount of heat (in kJ) necessary to raise the temperature of 47.8 g benzene by57.0 K. The specific heat capacity of benzene is 1.05 J/gCA) 1.61 kJB) 16.6 kJC) 2.59 kJD) 2.86 kJE) 3.85 kJAnswer: DDiff: 2 Page Ref: 6.417) Determine the specific heat capacity of an alloy that requires 59.3 kJ to raise the temperatureof 150.0 g alloy from 298 K to 398 K.A) 4.38 J/gCB) 2.29 J/gCC) 3.95 J/gCD) 2.53 J/gCE) 1.87 J/gCAnswer: CDiff: 2 Page Ref: 6.44Copyright (c) 2011 Pearson Education, Inc.

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18) 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 0.385J/gC.A) 1.51 kgB) 6.62 kgC) 1.26 kgD) 7.94 kgE) 3.64 kgAnswer: ADiff: 2 Page Ref: 6.419) Determine the final temperature of a gold nugget (mass = 376 g) that starts at 398 K andloses 4.85 kJ of heat to a snowbank when it is lost. The specific heat capacity of gold is 0.128J/gC.A) 133 KB) 398 KC) 187 KD) 297 KE) 377 KAnswer: DDiff: 3 Page Ref: 6.420) A balloon is inflated from 0.0100 L to 0.500 L against an external pressure of 10.00 atm.How much work is done in joules? 101.3 J = 1 L x atmA) -49.6 JB) 49.6 JC) 0.49 JD) -0.49 JE) -496 JAnswer: EDiff: 3 Page Ref: 6.421) Identify what a bomb calorimeter measures.A) measures H for aqueous solutionsB) measures E for combustion reactionsC) measures H for oxidation solutionsD) measures T for hydrolysis solutionsE) measures E for reduction reactionsAnswer: BDiff: 1 Page Ref: 6.55Copyright (c) 2011 Pearson Education, Inc.

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22) Calculate the change in internal energy (E) for a system that is giving off 25.0 kJ of heatand is changing from 12.00 L to 6.00 L in volume at 1.50 atm pressure. (Remember that 101.3 J= 1 Latm)A) +25.9 kJB) -16.0 kJC) -25.9 kJD) -24.1 kJE) 937 kJAnswer: DDiff: 2 Page Ref: 6.523) Calculate the change in internal energy (E) for a system that is absorbing 35.8 kJ of heatand is expanding from 8.00 to 24.0 L in volume at 1.00 atm. (Remember that 101.3 J = 1 Latm)A) +51.8 kJB) -15.8 kJC) -16.6 kJD) -29.3 kJE) +34.2 kJAnswer: EDiff: 2 Page Ref: 6.524) A 6.55 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in abomb calorimeter. If the temperature rose by 32.9C, use the information below to determine theheat capacity of the calorimeter.4 C6H5NH2(l) + 35 O2(g) 24 CO2(g) + 14 H2O(g) + 4 NO2(g)Hrxn= -1.28 x 104 kJA) 97.3 kJ/CB) 38.9 kJ/CC) 5.94 kJ/CD) 6.84 kJ/CE) 12.8 kJ/CAnswer: DDiff: 3 Page Ref: 6.56Copyright (c) 2011 Pearson Education, Inc.

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25) A 21.8 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter, according to thefollowing reaction. If the temperature rises from 25.0 to 62.3C, determine the heat capacity ofthe calorimeter. The molar mass of ethanol is 46.07 g/mol.C2H5OH(l) + 3 O2(g) 2 CO2(g) + 3 H2O(g) Hrxn = -1235 kJA) 4.99 kJ/CB) 5.65 kJ/CC) 63.7 kJ/CD) 33.1 kJ/CE) 15.7 kJ/CAnswer: EDiff: 3 Page Ref: 6.526) A 4.98 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in abomb calorimeter with a heat capacity of 4.25 kJ/C. If the temperature rose from 29.5C to69.8C, determine the value of Hcomb for aniline.A) +7.81 103 kJ/molB) -3.20 103 kJ/molC) +1.71 103 kJ/molD) -1.71 103 kJ/molE) -7.81 103 kJ/molAnswer: BDiff: 4 Page Ref: 6.527) The temperature rises from 25.00 C to 29.00 C in a bomb calorimeter when 3.50 g ofsucrose undergoes combustion in a bomb calorimeter. Calculate Erxn for the combustion ofsucrose in kJ/mol sucrose. The heat capacity of the calorimeter is 4.90 kJ/C . The molar massof sugar is 342.3 g/mol.A) - 1.92 103 kJ/moleB) 1.92 103 kJ/moleC) - 1.23 103 kJ/moleD) 2.35 104 kJ/moleAnswer: ADiff: 4 Page Ref: 6.57Copyright (c) 2011 Pearson Education, Inc.

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28) A 12.8 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter with a heat capacityof 5.65 kJ/C. Using the information below, determine the final temperature of the calorimeter ifthe initial temperature is 25.0C. The molar mass of ethanol is 46.07 g/mol.C2H5OH(l) + 3 O2(g) 2 CO2(g) + 3 H2O(g) Hrxn = -1235 kJA) 53.4CB) 28.1CC) 111CD) 85.7 CE) 74.2CAnswer: DDiff: 4 Page Ref: 6.529) A 35.6 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter, according to thefollowing reaction. If the temperature rose from 35.0 to 76.0C and the heat capacity of thecalorimeter is 23.3 kJ/C, what is the value of DHrxn? The molar mass of ethanol is 46.07g/mol.C2H5OH(l) + 3 O2(g) 2 CO2(g) + 3 H2O(g) Hrxn = ?A) -1.24 103 kJ/molB) +1.24 103 kJ/molC) -8.09 103 kJ/molD) -9.55 103 kJ/molE) +9.55 103 kJ/molAnswer: ADiff: 4 Page Ref: 6.530) A 6.55 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in abomb calorimeter with a heat capacity of 14.25 kJ/C. If the initial temperature was 32.9C, usethe 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)Hrxn= -1.28 x 104 kJA) 257CB) 46.6 CC) 48.7CD) 41.9CE) 931CAnswer: CDiff: 4 Page Ref: 6.58Copyright (c) 2011 Pearson Education, Inc.

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31) 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.C) Erxn is a measure of heat.D) Hrxn is the heat of reaction.E) Endothermic has a positive H.Answer: CDiff: 1 Page Ref: 6.632) Where does the energy absorbed during an endothermic reaction go?Answer: During an endothermic reaction, the products are higher in potential energy than thereactants. The thermal (kinetic) energy absorbed during reaction is used in forming productswith a higher potential energy.Diff: 1 Page Ref: 6.633) Explain the difference between H and DE.Answer: Change in enthalpy (H) only tracks the exchange of heat between a system and itssurroundings. Internal energy change (E) tracks both heat and work exchanged between asystem and its surroundings.Diff: 1 Page Ref: 6.634) Given w = 0, an endothermic reaction has the following.A) +H and -EB) - H and +EC) + H and +ED) - H and -EAnswer: CDiff: 1 Page Ref: 6.635) Which of the following processes is endothermic?A) the freezing of waterB) the combustion of propaneC) a hot cup of coffee (system) cools on a countertopD) the chemical reaction in a "hot pack" often used to treat sore musclesE) the vaporization of rubbing alcoholAnswer: EDiff: 1 Page Ref: 6.636) Which of the following processes is exothermic?A) the formation of dew in the morningB) the melting of iceC) the chemical reaction in a "cold pack" often used to treat injuriesD) the vaporization of waterE) None of the above are exothermic.Answer: ADiff: 1 Page Ref: 6.69Copyright (c) 2011 Pearson Education, Inc.

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37) Which of the following processes is endothermic?A) an atom emits a photonB) the condensation of waterC) an atom absorbs a photonD) the electron affinity of a fluorine atomE) None of the above processes are endothermic.Answer: CDiff: 1 Page Ref: 6.638) Using the following equation for the combustion of octane, calculate the heat of reaction for100.0 g of octane. The molar mass of octane is 114.33 g/mole.2 C8H18 + 25 O2 16 CO2 + 18 H2OHrxn = -11018 kJA) 4.82 x 103 kJB) 4.82 kJC) 9.64 x 103 kJD) 1.26 x 104 kJAnswer: ADiff: 3 Page Ref: 6.639) 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) Hrxn = +1207 kJA) 2.31 103 kJB) 4.33 103 kJC) 6.72 103 kJD) 1.68 103 kJE) 5.95 103 kJAnswer: DDiff: 3 Page Ref: 6.640) How much energy is evolved during the reaction of 48.7 g of Al, according to the reactionbelow? Assume that there is excess Fe2O3.Fe2O3(s) + 2 Al(s) Al2O3(s) + 2 Fe(s) Hrxn = -852 kJA) 415 kJB) 207 kJC) 241 kJD) 130 kJE) 769 kJAnswer: EDiff: 3 Page Ref: 6.610Copyright (c) 2011 Pearson Education, Inc.

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41) How much energy is evolved during the formation of 98.7 g of Fe, according to the reactionbelow?Fe2O3(s) + 2 Al(s) Al2O3(s) + 2 Fe(s) Hrxn = -852 kJA) 753 kJB) 1.51 x 103 kJC) 4.20 x 103 kJD) 482 kJE) 241 kJAnswer: ADiff: 3 Page Ref: 6.642) According to the following reaction, how much energy is required to decompose 55.0 kg ofFe3O4? The molar mass of Fe3O4 is 231.55 g/mol.Fe3O4(s) 3 Fe(s) + 2 O2(g)Hrxn = +1118 kJA) 1.10 106 kJB) 2.38 102 kJC) 2.66 105 kJD) 1.12 103 kJE) 3.44 104 kJAnswer: CDiff: 3 Page Ref: 6.643) Using the following thermochemical equation, determine the amount of heat produced per kgof CO2 formed during the combustion of benzene (C6H6).2 C6H6(l) + 15 O2(g) 12 CO2(g) + 6 H2O(g) Hrxn = -6278 kJA) 1.43 105 kJ/kg CO2B) 2.30 104 kJ/kg CO2C) 4.34 104 kJ/kg CO2D) 1.19 104 kJ/kg CO2E) 8.40 105 kJ/kg CO2Answer: DDiff: 3 Page Ref: 6.611Copyright (c) 2011 Pearson Education, Inc.

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44) Using the following thermochemical equation, determine the amount of heat produced fromthe combustion of 24.3 g benzene (C6H6). The molar mass of benzene is 78.11 g/mole.2 C6H6(l) + 15 O2(g) 12 CO2(g) + 6 H2O(g) Hrxn = -6278 kJA) 3910 g C6H6B) 1950 g C6H6C) 977 g C6H6D) 40.1 g C6H6E) 0.302 g C6H6Answer: CDiff: 3 Page Ref: 6.645) Using the following equation for the combustion of octane, calculate the amount of moles ofcarbon dioxide formed from 100.0 g of octane. The molar mass of octane is 114.33 g/mole. Themolar mass of carbon dioxide is 44.0095 g/mole.2 C8H18 + 25 O2 16 CO2 + 18 H2OHrxn = -11018 kJA) 18.18 molesB) 6.997 molesC) 14.00 molesD) 8.000 molesE) 10.93 molesAnswer: BDiff: 4 Page Ref: 6.646) Using the following equation for the combustion of octane, calculate the amount of moles ofoxygen that reacts with 100.0 g of octane. The molar mass of octane is 114.33 g/mole. Themolar mass of carbon dioxide is 44.0095 g/mole.2 C8H18 + 25 O2 16 CO2 + 18 H2O Hrxn = -11018 kJA) 18.18 molesB) 6.997 molesC) 14.00 molesD) 8.000 molesE) 10.93 molesAnswer: EDiff: 4 Page Ref: 6.612Copyright (c) 2011 Pearson Education, Inc.

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47) According to the following reaction, how much energy is evolved during the reaction of 32.5g B2H6 and 72.5 g Cl2? The molar mass of B2H6 is 27.67 g/mol.B2H6(g) + 6 Cl2(g) 2 BCl3(g) + 6 HCl(g)Hrxn = -1396 kJA) 1640 kJB) 238 kJC) 1430 kJD) 3070 kJE) 429 kJAnswer: BDiff: 4 Page Ref: 6.648) According to the following reaction, how much energy is evolved during the reaction of 2.50L B2H6 and 5.65 L Cl2 (Both gases are initially at STP)? The molar mass of B2H6 is 27.67g/mol.B2H6(g) + 6 Cl2(g) 2 BCl3(g) + 6 HCl(g) Hrxn = -1396 kJA) 58.7 kJB) 156 kJC) 215 kJD) 352 kJE) 508 kJAnswer: ADiff: 4 Page Ref: 6.649) According to the following thermochemical equation, what mass of HF (in g) must react inorder to produce 345 kJ of energy? Assume excess SiO2.SiO2(s) + 4 HF(g) SiF4(g) + 2 H2O(l) Hrxn = -184 kJA) 42.7 gB) 37.5 gC) 150. gD) 107 gE) 173 gAnswer: CDiff: 4 Page Ref: 6.613Copyright (c) 2011 Pearson Education, Inc.

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50) According to the following thermochemical equation, what mass of H2O (in g) must form inorder to produce 975 kJ of energy?SiO2(s) + 4 HF(g) SiF4(g) + 2 H2O(l) Hrxn = -184 kJA) 68.0 gB) 102 gC) 54.1 gD) 191 gE) 95.5 gAnswer: DDiff: 4 Page Ref: 6.651) Using the following equation for the combustion of octane, calculate the amount of grams ofcarbon dioxide formed from 100.0 g of octane. The molar mass of octane is 114.33 g/mole. Themolar mass of carbon dioxide is 44.0095 g/mole.2 C8H18 + 25 O2 16 CO2 + 18 H2O Hrxn = -11018 kJA) 800.1 gB) 307.9 gC) 260.1 gD) 792.3 gAnswer: BDiff: 5 Page Ref: 6.652) What volume of benzene (C6H6, d= 0.88 g/mL, molar mass = 78.11 g/mol) is required toproduce 1.5 x 103 kJ of heat according to the following reaction?2 C6H6(l) + 15 O2(g) 12 CO2(g) + 6 H2O(g) Hrxn = -6278 kJA) 75 mLB) 37 mLC) 21 mLD) 19 mLE) 42 mLAnswer: EDiff: 5 Page Ref: 6.653) Identify what a coffee cup calorimeter measures.A) measures H for aqueous solutionsB) measures E for combustion reactionsC) measures H for oxidation solutionsD) measures T for hydrolysis solutionsE) measures E for reduction reactionsAnswer: ADiff: 1 Page Ref: 6.714Copyright (c) 2011 Pearson Education, Inc.

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54) Which of the following statements is TRUE?A) State functions do not depend on the path taken to arrive at a particular state.B) DErxn can be determined using constant volume calorimetry.C) Energy is neither created nor destroyed, excluding nuclear reactions.D) Hrxn can be determined using constant pressure calorimetry.E) All of the above are true.Answer: EDiff: 1 Page Ref: 6.755) Two aqueous solutions are both at room temperature and are then mixed in a coffee cupcalorimeter. The reaction causes the temperature of the resulting solution to fall below roomtemperature. Which of the following statements is TRUE?A) The products have a lower potential energy than the reactants.B) This type of experiment will provide data to calculate Erxn.C) The reaction is exothermic.D) Energy is leaving the system during reaction.E) None of the above statements are true.Answer: EDiff: 2 Page Ref: 6.756) A piece of iron (mass = 25.0 g) at 398 K is placed in a styrofoam coffee cup containing 25.0mL of water at 298 K. Assuming that no heat is lost to the cup or the surroundings, what will thefinal temperature of the water be? The specific heat capacity of iron = 0.449 J/gC and water =4.18 J/gC.A) 348 KB) 308 KC) 287 KD) 325 KE) 388 KAnswer: BDiff: 5 Page Ref: 6.757) A student is preparing to perform a series of calorimetry experiments. She first wishes todetermine the calorimeter constant (Ccal) for her coffee cup calorimeter. She pours a 50.0 mLsample of water at 345 K into the calorimeter containing a 50.0 mL sample of water at 298 K.She carefully records the final temperature of the water as 317 K. What is the value of Ccal forthe calorimeter?A) 19 J/KB) 28 J/KC) 99 J/KD) 21 J/KE) 76 J/KAnswer: CDiff: 5 Page Ref: 6.715Copyright (c) 2011 Pearson Education, Inc.

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58) 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 35.00C and the temperature of theresulting solution was recorded as 37.00C, determine the Hrxn (in units of kJ/mol NaOH) forthe neutralization reaction between aqueous NaOH and HCl. Assume 1) that no heat is lost tothe calorimeter or the surroundings, and 2) that the density and the heat capacity of the resultingsolution are the same as water.A) -55.7 kJ/mol NaOHB) -169 kJ/mol NaOHC) -16.7 kJ/mol NaOHD) -27.9 kJ/mol NaOHE) - 34.4 kJ/mol NaOHAnswer: ADiff: 5 Page Ref: 6.759) Two solutions, initially at 24.60C, are mixed in a coffee cup calorimeter (Ccal = 15.5 J/C).When a 100.0 mL volume of 0.100 M AgNO3 solution is mixed with a 100.0 mL sample of0.200 M NaCl solution, the temperature in the calorimeter rises to 25.30C. Determine theDHrxn for the reaction as written below. Assume that the density and heat capacity of thesolutions is the same as that of water.NaCl (aq) + AgNO3(aq) AgCl(s) + NaNO3(aq) DHrxn = ?A) -35 kJB) -69 kJC) -250 kJD) -16 kJE) -140 kJAnswer: BDiff: 5 Page Ref: 6.760) Two solutions, initially at 24.69C, are mixed in a coffee cup calorimeter (Ccal = 105.5J/C). When a 200.0 mL volume of 0.100 M AgNO3 solution is mixed with a 100.0 mL sampleof 0.100 M NaCl solution, the temperature in the calorimeter rises to 25.16C. Determine theDHrxn, in units of kJ/mol AgCl. Assume that the density and heat capacity of the solutions isthe same as that of water. Hint: Write a balanced reaction for the process.A) -32 kJ/mol AgClB) -78 kJ/mol AgClC) -64 kJ/mol AgClD) -25 kJ/mol AgClE) -59 kJ/mol AgClAnswer: CDiff: 5 Page Ref: 6.716Copyright (c) 2011 Pearson Education, Inc.

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61) Use the standard reaction enthalpies given below to determine Hrxn for the followingreaction:P4(g) + 10 Cl2(g) 4PCl5(s) Hrxn = ?Given:PCl5(s) PCl3(g) + Cl2(g) Hrxn= +157 kJP4(g) + 6 Cl2(g) 4 PCl3(g) Hrxn = -1207 kJA) -1835 kJB) -1364 kJC) -1050. kJD) -1786 kJE) -2100. kJAnswer: ADiff: 2 Page Ref: 6.862) Use the standard reaction enthalpies given below to determine Hrxn for the followingreaction:2 NO(g) + O2(g) 2 NO2(g) Hrxn = ?Given:N2(g) + O2(g) 2 NO(g)Hrxn = +183 kJ1/2 N2(g) + O2(g) NO2(g) Hrxn = +33 kJA) -150. kJB) -117 kJC) -333 kJD) +115 kJE) +238 kJAnswer: BDiff: 2 Page Ref: 6.817Copyright (c) 2011 Pearson Education, Inc.

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63) Use the standard reaction enthalpies given below to determine Hrxn for the followingreaction:2 S(s) + 3 O2(g) 2 SO3(g) Hrxn = ?Given:SO2(g) S(s) + O2(g)Hrxn = +296.8 kJ2 SO2(g) + O2(g) 2 SO3(g) Hrxn = -197.8 kJA) -494.6 kJB) -692.4 kJC) -791.4 kJD) 1583 kJE) -293.0 kJAnswer: CDiff: 2 Page Ref: 6.864) Use the standard reaction enthalpies given below to determine Hrxn for the followingreaction:4 SO3(g) 4 S(s) + 6 O2(g) Hrxn = ?Given:SO2(g) S(s) + O2(g)Hrxn = +296.8 kJ2 SO2(g) + O2(g) 2 SO3(g) Hrxn = -197.8 kJA) -494.6 kJB) -692.4 kJC) -791.4 kJD) 1583 kJE) -293.0 kJAnswer: DDiff: 2 Page Ref: 6.865) Which of the following is not a standard state?A) for a solid, it is 25FB) for a liquid, it is 25CC) for a solution, it is 1 atmD) for a solution, it is 1 ME) for a liquid, it is 1 atmAnswer: ADiff: 1 Page Ref: 6.918Copyright (c) 2011 Pearson Education, Inc.

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66) Identify a substance that is not in its standard state.A) COB) CaC) H2D) O2E) NeAnswer: ADiff: 1 Page Ref: 6.967) Identify a substance that is not in its standard state.A) O2B) CaC) HD) O3E) NeAnswer: CDiff: 1 Page Ref: 6.968) Which of the following processes is exothermic?A) the ionization of a lithium atomB) the breaking of a Cl-Cl bondC) the sublimation of dry ice (CO2(s))D) the reaction associated with DHf for an ionic compoundE) All of the above processes are exothermic.Answer: DDiff: 1 Page Ref: 6.969) Choose the reaction that illustrates Hf for Ca(NO3)2.A) Ca(s) + N2(g) + 3O2(g) Ca(NO3)2(s)B) Ca2+(aq) + 2 NO3-(aq) Ca(NO3)2(aq)C) Ca(s) + 2 N(g) + 6 O(g) Ca(NO3)2(s)D) Ca(NO3)2(aq) Ca2+(aq) + 2 NO3-(aq)E) Ca(NO3)2(s) Ca(s) + N2(g) + 3O2(g)Answer: ADiff: 1 Page Ref: 6.970) Choose the reaction that illustrates Hf for NaHCO3.A) Na(s) + H2(g) + C(s) + O2(g) NaHCO3 (s)B) Na+(aq) + HCO3 -1 (aq) NaHCO3 (s)C) Na+(aq) + H2O (l) + CO2 (g) NaHCO3 (s)D) Na(s) + 1/2 H2(g) + C(s) + 3/2 O2(g) NaHCO3 (s)E) Na(s) + 2 H(g) + C(s) + 3 O(g) NaHCO3 (s)Answer: DDiff: 1 Page Ref: 6.919Copyright (c) 2011 Pearson Education, Inc.

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71) Choose the thermochemical equation that illustrates Hf for Li2SO4.A) 2 Li+(aq) + SO42-(aq) Li2SO4(aq)B) 2 Li(s) + 1/8 S8(s, rhombic) + 2 O2(g) Li2SO4(s)C) Li2SO4(aq) 2 Li+(aq) + SO42-(aq)D) 8 Li2SO4(s) 16 Li(s) + S8(s, rhombic) + 16 O2(g)E) 16 Li(s) + S8(s, rhombic) + 16 O2(g) 8 Li2SO4(s)Answer: BDiff: 1 Page Ref: 6.972) Use the Hf information provided to calculate Hrxn for the following:Hf (kJ/mol) SO2Cl2 (g) + 2 H2O(l) 2 HCl(g) + H2SO4(l) Hrxn = ?SO2Cl2(g) -364H2O(l)-286HCl(g)-92H2SO4(l)-814A) -256 kJB) +161 kJC) -62 kJD) +800. kJE) -422 kJAnswer: CDiff: 2 Page Ref: 6.973) Use the Hf and Hrxn information provided to calculate Hf for IF:Hf (kJ/mol) IF7(g) + I2(g) IF5(g) + 2 IF(g) Hrxn = -89 kJIF7(g)-941IF5(g)-840A) 101 kJ/molB) -146 kJ/molC) -190. kJ/molD) -95 kJ/molE) 24 kJ/molAnswer: DDiff: 2 Page Ref: 6.920Copyright (c) 2011 Pearson Education, Inc.

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74) Use the Hf and Hrxn information provided to calculate Hf for SO3(g):Hf (kJ/mol) 2 SO2(g) + O2(g) 2 SO3(g) Hrxn = -198 kJSO2(g)-297A) -792 kJ/molB) -248 kJ/molC) -495 kJ/molD) -578 kJ/molE) -396 kJ/molAnswer: EDiff: 2 Page Ref: 6.975) Use the information provided to determine Hrxn for the following reaction:Hf (kJ/mol)CH4(g) + 4 Cl2(g) CCl4(g) + 4 HCl(g)Hrxn = ?CH4(g)-75CCl4(g)-96HCl(g)-92A) -389 kJB) -113 kJC) +113 kJD) -71 kJE) +79 kJAnswer: ADiff: 2 Page Ref: 6.976) Use the information provided to determine Hrxn for the following reaction:Hf (kJ/mol)CH4(g) + 3 Cl2(g) CHCl3(l) + 3 HCl(g)Hrxn = ?CH4(g)-75CHCl3(l)-134HCl(g)-92A) -151 kJB) -335 kJC) +662 kJD) +117 kJE) -217 kJAnswer: BDiff: 2 Page Ref: 6.921Copyright (c) 2011 Pearson Education, Inc.

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77) Use the information provided to determine Hrxn for the following reaction:Hf (kJ/mol)3 Fe2O3(s) + CO(g) 2 Fe3O4(s) + CO2(g) Hrxn = ?Fe2O3(s)-824Fe3O4(s)-1118CO(g)-111CO2(g)-394A) +277 kJB) -577 kJC) -47 kJD) +144 kJE) -111 kJAnswer: CDiff: 2 Page Ref: 6.978) Which of the following statements is TRUE?A) The burning of fossil fuels contributes to global warming.B) Cars that run on hydrogen fuel cells are environmentally friendly.C) The more energy produced per kg of CO2 produced, the better the fuel.D) Acid rain is one of the problems associated with the combustion of fossil fuels.E) All of the above are true.Answer: EDiff: 1 Page Ref: 6.1079) Which of the following is not a major contributor to energy consumption?A) residentialB) commercialC) transportationD) industrialE) atmosphericAnswer: EDiff: 1 Page Ref: 6.1080) Identify the greatest source of energy in the U. S.A) petroleumB) natural gasC) woodD) coalE) nuclear powerAnswer: ADiff: 1 Page Ref: 6.1022Copyright (c) 2011 Pearson Education, Inc.

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81) Identify a greenhouse gas.A) CO2B) O2C) COD) NOE) NO2Answer: ADiff: 1 Page Ref: 6.1082) Identify an energy source that is not renewable.A) solarB) hydroelectricC) coalD) windE) sunAnswer: CDiff: 1 Page Ref: 6.10Algorithmic Questions1) For a process at constant pressure, 49,600 calories of heat are released. This quantity of heatis equivalent toA) 4.82 10- 6 J.B) 1.19 104 J.C) 1.24 104 J.D) 2.08 105 J.Answer: DDiff: 2 Page Ref: 6.12) Calculate the kinetic energy of a 150 g baseball moving at a speed of 39. m/s ( 87 mph).A) 5.8 JB) 1.1 102 JC) 5.8 103 JD) 1.1 105 JAnswer: BDiff: 2 Page Ref: 6.23) Calculate the work,w, gained or lost by the system when a gas expands from 15 L to 40 Lagainst a constant external pressure of 1.5 atm. 101.3 L atm = 101 JA) - 6.1 kJB) - 3.8 kJC) + 3.8 kJD) + 6.1 kJAnswer: BDiff: 2 Page Ref: 6.423Copyright (c) 2011 Pearson Education, Inc.

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4) The specific heat capacity of liquid mercury is 0.14 J/gK. How many joules of heat are neededto raise the temperature of 5.00 g of mercury from 15.0C to 36.5C?A) 7.7 102 JB) 15 JC) 36 JD) 0.0013 JE) 1.7 JAnswer: BDiff: 3 Page Ref: 6.45) The specific heat capacity of solid copper metal is 0.385 J/gK. How many joules of heat areneeded to raise the temperature of a 1.55-kg block of copper from 33.0C to 77.5C?A) 1.79 JB) 26.6 JC) 2.66 JD) 5.58 JE) 0.00558 JAnswer: CDiff: 3 Page Ref: 6.46) A 5.00-g sample of liquid water at 25.0 C is heated by the addition of 84.0 J of energy. Thefinal temperature of the water is __________ C. The specific heat capacity of liquid water isA) 95.2B) 25.2C) -21.0D) 29.0E) 4.02Answer: DDiff: 3 Page Ref: 6.47) A 6.50-g sample of copper metal at 25.0C is heated by the addition of 84.0 J of energy. Thefinal temperature of the copper is __________C. The specific heat capacity of copper is0.38 J/gK.A) 29.9B) 25.0C) 9.0D) 59.0E) 34.0Answer: DDiff: 3 Page Ref: 6.424Copyright (c) 2011 Pearson Education, Inc.

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8) The specific heat capacity of liquid water is 4.18 J/g-K. How many joules of heat are neededto raise the temperature of 5.00 g of water from 25.1C to 65.3C?A) 48.1 JB) 840 JC) 1.89 103 JD) 2.08 10-2 JE) 54.4 JAnswer: BDiff: 3 Page Ref: 6.49) The specific heat capacity of methane gas is 2.20 J/g-K. How many joules of heat are neededto raise the temperature of 5.00 g of methane from 36.0C to 75.0C?A) 88.6 JB) 429 JC) 1221 JD) 0.0113 JE) 22.9 JAnswer: BDiff: 3 Page Ref: 6.410) The specific heat of copper is 0.385 J/(g C). If 34.2 g of copper, initially at 24.0C,absorbs 4.689 kJ, what will be the final temperature of the copper?A) 24.4CB) 26.8CC) 356CD) 380CAnswer: DDiff: 3 Page Ref: 6.411) It takes 11.2 kJ of energy to raise the temperature of 145 g of benzene from 23.0C to68.0C. What is the specific heat of benzene?A) 1. 14 J/(g C)B) 1.72 J/(g C)C) 3.48 J/(g C)D) 5. 25 J/(g C)Answer: BDiff: 3 Page Ref: 6.412) A 50.0-g sample of liquid water at 25.0C is mixed with 29.0 g of water at 45.0C. Thefinal temperature of the water is __________C.A) 102B) 27.6C) 35.0D) 142E) 32.3Answer: EDiff: 3 Page Ref: 6.425Copyright (c) 2011 Pearson Education, Inc.

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13) What is the enthalpy change (in kJ) of a chemical reaction that raises the temperature of250.0 ml of solution having a density of 1.25 g/ml by 7.80C? (The specific heat of the solutionis 3.74 joules/gramK.)A) -7.43 kJB) -12.51 kJC) 8.20 kJD) -9.12 kJE) 6.51 kJAnswer: DDiff: 4 Page Ref: 6.414) The combustion of titanium with oxygen produces titanium dioxide:Ti (s) + O2 (g) TiO2 (s)When 2.060 g of titanium is combusted in a bomb calorimeter, the temperature of thecalorimeter increases from 25.00C to 91.60C. In a separate experiment, the heat capacity ofthe calorimeter is measured to be 9.84 kJ/K. The heat of reaction for the combustion of a mole ofTi in this calorimeter is __________ kJ/mol.A) 14.3B) 19.6C) -311D) -0.154E) -1.52 104Answer: EDiff: 4 Page Ref: 6.415) When 0.455 g of anthracene, C14H10, is combusted in a bomb calorimeter that has a waterjacket containing 500.0 g of water, the temperature of the water increases by 8.63C. Assumingthat the specific heat of water is 4.18 J/(g C), and that the heat absorption by the calorimeter isnegligible, estimate the enthalpy of combustion per mole of anthracene.A) +39.7 kJ/molB) -39.7 kJ/molC) -7060 kJ/molD) -8120 kJ/molAnswer: CDiff: 2 Page Ref: 6.516) For a particular process that is carried out at constant pressure,q= 145 kJ andw= - 35 kJ.Therefore,A) E= 110 kJ and H= 145 kJ.B) E= 145 kJ and H= 110 kJ.C) E= 145 kJ and H= 180 kJ.D) E= 180 kJ and H= 145 kJ.Answer: ADiff: 2 Page Ref: 6.626Copyright (c) 2011 Pearson Education, Inc.

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17) When 5.00 mol of benzene is vaporized at a constant pressure of 1.00 atm and at its normalboiling point of 80.1C, 169.5 kJ are absorbed andPVfor the vaporization process is equal to14.5 kJ thenA) E= 155.0 kJ and H= 169.5 kJ.B) E= 184.0 kJ and H= 169.5 kJ.C) E= 169.5 kJ and H= 184.0 kJ.D) E= 169.5 kJ and H= 155.0 kJ.Answer: ADiff: 4 Page Ref: 6.618) When 10.00 moles of H2(g) reacts with 5.000 mol of O2(g) to form 10.00 mol of H2O(l) at25C and a constant pressure of 1.00 atm. If 683.0 kJ of heat are released during this reaction,andPVis equal to - 37.00 kJ, thenA) H = + 683.0 kJ and E = + 720.0 kJ.B) H = + 683.0 kJ and E = + 646.0 kJ.C) H = - 683.0 kJ and E = - 646.0 kJ.D) H = - 683.0 kJ and E = - 720.0 kJ.Answer: CDiff: 4 Page Ref: 6.619) At 1 atm pressure, the heat of sublimation of gallium is 277 kJ/mol and the heat ofvaporization is 271 kJ/mol. To the correct number of significant figures, how much heat isrequired to melt 4.50 mol of gallium at 1 atm pressure?A) 6 kJB) 27 kJC) 250 kJD) 274 kJAnswer: BDiff: 4 Page Ref: 6.620) How much heat is absorbed/released when 35.00 g of NH3(g) reacts in the presence ofexcess O2(g) to produce NO(g) and H2O(l) according to the following chemical equation?4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(l) H = 1168 kJA) 600.1 kJ of heat are absorbed.B) 600.1 kJ of heat are released.C) 2400 kJ of heat are absorbed.D) 2400 kJ of heat are released.Answer: ADiff: 4 Page Ref: 6.627Copyright (c) 2011 Pearson Education, Inc.

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21) How much heat is absorbed when 45.00 g of C(s) reacts in the presence of excess SO2(g) toproduce CS2(l) and CO(g) according to the following chemical equation?5 C(s) + 2 SO2(g) CS2(l) + 4 CO(g) H = 239.9 kJA) 179.8 kJB) 239.9 kJC) 898.5 kJD) 2158 kJAnswer: ADiff: 4 Page Ref: 6.622) At constant pressure, the combustion of 15.0 g of C2H6(g) releases 777 kJ of heat. What isHfor the reaction given below?2 C2H6(g) + 7 O2(g) 4 CO2(g) + 6 H2O(l).A) - 129 kJB) - 779 kJC) -1560 kJD) -3120 kJAnswer: DDiff: 4 Page Ref: 6.623) When 1.50 mol of CH4(g) reacts with excess Cl2(g) at constant pressure according to thechemical equation shown below, 1062 kJ of heat are released. Calculate the value of Hfor thisreaction, as written.2 CH4(g) + 3 Cl2(g) 2 CHCl3(l) + 3 H2(g)H= ?A) -1420 kJB) -708 kJC) +708 kJD) +1420 kJAnswer: ADiff: 4 Page Ref: 6.624) In the presence of excess oxygen, methane gas burns in a constant-pressure system to yieldcarbon dioxide and water:CH4 (g) + 2O2 (g) CO2 (g) + 2H2O (l) H = -890.0 kJCalculate the value of q (kJ) in this exothermic reaction when 1.70 g of methane is combusted atconstant pressure.A) -94.6 kJB) 0.0306 kJC) -0.0106 kJD) 32.7 kJE) -9.46 104 kJAnswer: ADiff: 3 Page Ref: 6.728Copyright (c) 2011 Pearson Education, Inc.

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25) Hydrogen peroxide decomposes to water and oxygen at constant pressure by the followingreaction:2H2O2 (l) 2H2O (l) + O2 (g)H = -196 kJCalculate the value of q (kJ) in this exothermic reaction when 4.00 g of hydrogen peroxidedecomposes at constant pressure?A) -23.1 kJB) -11.5 kJC) - 0.0217 kJD) 1.44 kJE) -2.31 104 kJAnswer: BDiff: 3 Page Ref: 6.726) When 1.50 g of Ba(s) is added to 100.00 g of water in a container open to the atmosphere,the reaction shown below occurs and the temperature of the resulting solution rises from 22.00Cto 33.10C. If the specific heat of the solution is 4.18 J/(g C), calculate Hfor the reaction, aswritten.Ba(s) + 2 H2O(l) Ba(OH)2(aq) + H2(g)= ?A) -431 kJB) -3.14 kJC) +3.14 kJD) +431 kJAnswer: ADiff: 4 Page Ref: 6.727) Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide according tothe chemical equation shown below. When 0.0 25 mol of Na is added to 100.00 g of water, thetemperature of the resulting solution rises from 25.00C to 35.75C. If the specific heat of thesolution is 4.18 J/(g C), calculate Hfor the reaction, as written.2 Na(s) + 2 H2O(l) 2 NaOH(aq) + H2(g) H=?A) -5.41 kJB) -90.0 kJC) -180 kJD) -360 kJAnswer: DDiff: 4 Page Ref: 6.729Copyright (c) 2011 Pearson Education, Inc.

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28) When 50.0 mL of 0.400 M Ca(NO3)2 is added to 50.0 mL of 0.800 M NaF, CaF2precipitates, as shown in the net ionic equation below. The initial temperature of both solutions is23.0C. Assuming that the reaction goes to completion, and that the resulting solution has amass of 100.00 g and a specific heat of 4.18 J/(g C), calculate the final temperature of thesolution.Ca2+(aq) + 2 F-(aq) CaF2(s) H = -11.5 kJA) 22.45CB) 23.55CC) 24.10CD) 24.65CAnswer: BDiff: 4 Page Ref: 6.7Matching QuestionsMatch the following.A) kinetic energyB) chemical energyC) potential energyD) thermal energy1) energy associated with the motion of an objectDiff: 1 Page Ref: 6.22) energy associated with the temperature of an objectDiff: 1 Page Ref: 6.23) energy associated with the position of an objectDiff: 1 Page Ref: 6.24) energy associated with the relative positions of electrons and nuclei in atoms and moleculesDiff: 1 Page Ref: 6.2Answers: 1) A 2) D 3) C 4) B30Copyright (c) 2011 Pearson Education, Inc.

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Match the following.A) energy flows out of system into the surroundingsB) work done on the system by the surroundingsC) work done by the system on the surroundingsD) system gains thermal energy from the surroundingsE) system loses thermal energy to the surroundingsF) energy flows into the system from the surroundings5) -EDiff: 1 Page Ref: 6.36) +EDiff: 1 Page Ref: 6.37) -wDiff: 1 Page Ref: 6.38) +wDiff: 1 Page Ref: 6.39) -qDiff: 1 Page Ref: 6.310) + qDiff: 1 Page Ref: 6.3Answers: 5) A 6) F 7) C 8) B 9) E 10) DShort Answer Questions1) Describe the energy changes that occur when a book is held 6 ft off the floor and thendropped.Answer: The book starts out with a certain amount of potential energy (stored energy due toposition). When it begins to drop, that potential energy is then converted to kinetic energy(energy of motion).Diff: 1 Page Ref: 6.22) Define chemical energy.Answer: Chemical energy is the energy associated with the relative positions of electrons andnuclei in atoms and molecules.Diff: 1 Page Ref: 6.23) Give the temperature and pressure for the standard state for a liquid.Answer: 1 atmosphere and 25CDiff: 1 Page Ref: 6.9