Multiple ChoiceThe oxidation of ammonia is illustrated by the following equation:4 NH3 (g) + 5 O2 (g) → 4 NO (g) + 6 H2O (g)Calculate the enthalpy of reaction, ΔHRxn, based on the given standard heats of formation. 2166views
Multiple ChoiceConsider the following equation: 2 ClF3(g) + 2 NH3(g) → 1 N2(g) + 6 HF (g) + 6 Cl2(g) ΔHrxn = –1196 kJDetermine the standard enthalpy of formation for chlorine trifluoride, ClF3. 3098views3comments
Multiple ChoiceFind ΔHrxn for the following reaction: N2 + 2 O2 → 2 NO2Based on the following data. 2 NO → N2 + O2 ΔH = −180 kJ 2 NO + O2 → 2 NO2 ΔH = −112 kJ261views
Multiple ChoiceUsing standard thermodynamic data, calculate ΔH°rxn for the following: 2 C2H2 (g) + 5 O2 (g) → 4 CO2 (g) + 2 H2O (l)303views
Textbook QuestionA table of standard enthalpies of formation (ΔH°f) gives a value of −467.9 kJ/mol for NaNO3(s). Which reaction has a ΔH° value of −467.9 kJ? (a) Na+ (aq) + NO3−(aq) → NaNO3(s) (b) Na(s) + N(g + O3(g) → NaNO3(s) (c) Na(s) + 1/2 N2(g) + 3/2 O2(g) → NaNO3(s) (d) 2 Na(s) + N2(g) + 3 O2(g) → 2 NaNO3(s)2425views
Textbook QuestionWhat is ΔH for the explosion of nitroglycerin? (LO 9.14) 2 C3H5(NO3)3(l) → 3 N2(g) + 1/2 O2(g) + 6 CO2(g) + 5 H2O(g) (a) −315.0 kJ (b) −4517 kJ (c) −3425 kJ (d) −3062 kJ822viewsTextbook QuestionAtomic hydrogen (H) is used in welding (AHW). The atoms recombine to hydrogen molecules with a large release of heat according to the following reaction: 2 H1g2 ¡H21g2 (b) Which has the higher enthalpy under these conditions, 2 H1g2 or H21g2?585viewsTextbook QuestionConsider the following equilibrium between oxides of nitrogen 3 NO(g) ⇌ NO2(g) + N2O(g) (a) Use data in Appendix C to calculate ΔH° for this reaction.461viewsTextbook QuestionMethanol 1CH3OH2 can be made by the reaction of CO with H2: CO1g2 + 2 H21g2 Δ CH3OH1g2 (a) Use thermochemical data in Appendix C to calculate H for this reaction.1091viewsTextbook QuestionAcetylene 1C2H21g22 is used for welding because oxyacetylene is the hottest burning common fuel gas. Using standard enthalpies of formation, calculate the quantity of heat produced when 10 g of acetylene is completely combusted in air under standard conditions.578viewsTextbook QuestionThe fuel in high-efficiency natural-gas vehicles consists primarily of methane (CH4). (a) How much heat is produced in burning 1 mol of CH4(g) under standard conditions if reactants and products are brought to 298 K and H2O(l) is formed?518viewsTextbook QuestionUsing values from Appendix C, calculate the value of H for each of the following reactions: (a) CaO(s) + 2 HF(g) → CaF2(s) + H2O(g)1060viewsTextbook QuestionZinc metal reacts with hydrochloric acid according to the balanced equation: Zn(s) + 2 HCl(aq)¡ZnCl2(aq) + H2( g) When 0.103 g of Zn(s) is combined with enough HCl to make 50.0 mL of solution in a coffee-cup calorimeter, all of the zinc reacts, raising the temperature of the solution from 22.5 °C to 23.7 °C. Find ΔHrxn for this reaction as written. (Use 1.0 g>mL for the density of the solution and 4.18 J>g # °C as the specific heat capacity.)27027viewsTextbook QuestionComplete combustion of 1 mol of acetone 1C3H6O2 liberates 1790 kJ: C3H6O1l2 + 4 O21g2 ¡ 3 CO21g2 + 3 H2O1l2 H° = -1790 kJ Using this information together with the standard enthalpies of formation of O21g2, CO21g2, and H2O1l2 from Appendix C, calculate the standard enthalpy of formation of acetone.2644viewsTextbook QuestionCalcium carbide 1CaC22 reacts with water to form acetylene 1C2H22 and Ca1OH22. From the following enthalpy of reaction data and data in Appendix C, calculate Hf° for CaC21s2: CaC21s2 + 2 H2O1l2 ¡ Ca1OH221s2 + C2H21g2 H° = -127.2 kJ961viewsTextbook QuestionGasoline is composed primarily of hydrocarbons, including many with eight carbon atoms, called octanes. One of the cleanest–burning octanes is a compound called 2,3,4- trimethylpentane, which has the following structural formula: The complete combustion of one mole of this compound to CO21g2 and H2O1g2 leads to H° = -5064.9 kJ. (b) By using the information in this problem and data in Table 5.3, calculate Hf° for 2,3,4-trimethylpentane.1186viewsTextbook QuestionEthanol (C2H5OH) is blended with gasoline as an automobile fuel. (d) Calculate the mass of CO2 produced per kJ of heat emitted.727viewsTextbook QuestionEthanol (C2H5OH) is blended with gasoline as an automobile fuel. (c) Calculate the heat produced per liter of ethanol by combustion of ethanol under constant pressure. Ethanol has a density of 0.789 g/mL.892viewsTextbook QuestionMethanol 1CH3OH2 is used as a fuel in race cars. (b) Calculate the standard enthalpy change for the reaction, assuming H2O1g2 as a product.750viewsTextbook QuestionHydrazine (N2H4) is a fuel used by some spacecraft. It is normally oxidized by N2O4 according to the equation: N2H4 (l) + N2O4 (g) → 2 N2O (g) + 2 H2O (g) Calculate ΔH°rxn for this reaction using standard enthalpies of formation.3797views1commentsTextbook QuestionPentane (C5H12) is a component of gasoline that burns according to the following balanced equation: C5H12(l ) + 8 O2( g)¡5 CO2( g) + 6 H2O( g) Calculate ΔH °rxn for this reaction using standard enthalpies of formation. (The standard enthalpy of formation of liquid pentane is -146.8 kJ>mol.)8448views3rankTextbook QuestionUse standard enthalpies of formation to calculate ΔH °rxn for each reaction. d. Cr2O3(s) + 3 CO( g)¡2 Cr(s) + 3 CO2( g)1053viewsTextbook QuestionUse standard enthalpies of formation to calculate ΔH °rxn for each reaction. c. 3 NO2( g) + H2O(l )¡2 HNO3(aq) + NO( g)1272viewsTextbook QuestionUse standard enthalpies of formation to calculate ΔH °rxn for each reaction. a. C2H4( g) + H2( g)¡C2H6( g)992viewsTextbook QuestionUse standard enthalpies of formation to calculate ΔH °rxn for each reaction. a. 2 H2S( g) + 3 O2( g)¡2 H2O(l ) + 2 SO2( g)387viewsTextbook QuestionUse standard enthalpies of formation to calculate ΔH °rxn for each reaction. b. SO2( g) + 12 O2( g)¡SO3( g)1880viewsTextbook QuestionEthanol (C2H5OH) can be made from the fermentation of crops and has been used as a fuel additive to gasoline. Write a balanced equation for the combustion of ethanol and calculate ΔH °rxn.1692viewsTextbook QuestionTop fuel dragsters and funny cars burn nitromethane as fuel according to the balanced combustion equation: 2 CH3NO2(l ) + 32O2( g)¡2 CO2( g) + 3 H2O(l ) + N2( g) ΔH °rxn = -1418 kJ The enthalpy of combustion for nitromethane is -709.2 kJ>mol. Calculate the standard enthalpy of formation (ΔH °f ) for nitromethane.3091views3commentsTextbook QuestionThe explosive nitroglycerin (C3H5N3O9) decomposes rapidly upon ignition or sudden impact according to the balanced equation: 4 C3H5N3O9(l )¡12 CO2( g) + 10 H2O( g) + 6 N2( g) + O2( g) ΔH °rxn = -5678 kJ Calculate the standard enthalpy of formation (ΔH °f ) for nitroglycerin.6989viewsTextbook QuestionMethanol (CH3OH) has been suggested as a fuel to replace gasoline. Find ΔH °rxn, and determine the mass of carbon dioxide emitted per kJ of heat produced. Use the information from the previous exercise to calculate the same quantity for octane, C8H18. How does methanol compare to octane with respect to global warming?1178viewsTextbook QuestionAll the oxides of nitrogen have positive values of ΔGf° at 298 K, but only one common oxide of nitrogen has a positive ΔSf°. Identify that oxide of nitrogen without reference to thermodynamic data and explain.402viewsTextbook QuestionThe standard enthalpies of formation of gaseous propyne (C3H4), propylene (C3H6), and propane (C3H8) are +185.4, +20.4, and -103.8 kJ/mol, respectively. (c) Which is the most efficient fuel in terms of heat evolved per unit mass?1912viewsTextbook QuestionThe standard enthalpies of formation of gaseous propyne (C3H4), propylene (C3H6), and propane (C3H8) are +185.4, +20.4, and -103.8 kJ/mol, respectively. (b) Calculate the heat evolved on combustion of 1 kg of each substance.591viewsTextbook QuestionIt is interesting to compare the 'fuel value' of a hydrocarbon in a hypothetical world where oxygen is not the combustion agent. The enthalpy of formation of CF4(g) is -679.9 kJ/mol. Which of the following two reactions is the more exothermic?CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g)CH4(g) + 4 F2(g) → CF4(g) + 4 HF(g)844viewsTextbook QuestionWhat is a compound's standard heat of formation?543viewsTextbook QuestionUse standard enthalpies of formation to calculate the standard change in enthalpy for the melting of ice. (The ΔH °f for H2O(s) is -291.8 kJ/mol.)1839viewsTextbook QuestionCalculate ∆H°f in kJ/mol for benzene, C6H6, from the following data: 2 C6H6(l) + 15 O2(g) → 12 CO2(g) + 6 H2O(l) ∆H°=-6534 kJ ∆H°f (CO2) = -393.5 kJ/mol ∆H°f(H2O) = -285.8 kJ/mol3429views1rankTextbook QuestionAcetylene (C2H2) and nitrogen (N2) both contain a triple bond, but they differ greatly in their chemical properties. (b) By referring to Appendix C, look up the enthalpies of formation of acetylene and nitrogen. Which compound is more stable?329viewsTextbook QuestionHydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. To compare the energy of these fuels to that of octane (C8H18), calculate the energy released per kilogram of octane.687viewsTextbook QuestionHydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. Which fuel contains the most energy in the least mass?589viewsTextbook QuestionAcetic acid (CH3CO2H), whose aqueous solutions are known as vinegar, is prepared by reaction of ethyl alcohol (CH3CH2OH) with oxygen: CH3CH2OH(l) + O2(g) → CH3CO2H(l) + H2O(l) Use the following data to calculate ∆H° in kilojoules for the reaction: ∆H°f [CH3CH2OH(l)] = -277.7 kJ/mol ∆H°f [CH3CO2H(l)] = -484.5 kJ/mol ∆H°f [H2O(l)] = -285.8 kJ/mol3155viewsTextbook QuestionStyrene (C8H8), the precursor of polystyrene polymers, has a standard heat of combustion of -4395 kJ/mol. Write a balanced equation for the combustion reaction, and calculate ΔH°f for styrene in kJ/mol. ΔH°f [CO2(g)] = -393.5 kJ/mol; ΔH°f [H2O(l)] = -285.8 kJ/mol1114viewsTextbook QuestionUnder certain nonstandard conditions, oxidation by O2( g) of 1 mol of SO2( g) to SO3( g) absorbs 89.5 kJ. The enthalpy of formation of SO3( g) is -204.2 kJ under these conditions. Find the enthalpy of formation of SO2( g).3218viewsTextbook QuestionMethyl tert-butyl ether (MTBE), C5H12O, a gasoline additive used to boost octane ratings, has ΔH°f = -313.6 kJ/mol. Write a balanced equaiton for its combustion reaciton, and calcualte its standard heat of combustion in kilojoules1128viewsTextbook QuestionMethyl tert-butyl ether (MTBE) is prepared by reaciton of methanol (l) (ΔH°f = -239.2 kJ/mol) with 2-methyl-propene (g), according to the requation Calculate ΔH°f in kJ/mol for 2-methylpropene714viewsTextbook QuestionGiven the standard heats of formation shown in Appendix B, what is ΔH° in kilojoules for the reaciton CaCO3(s) → CaO(s) + CO2(g)?335viewsTextbook QuestionThe ΔH for the oxidation of sulfur in the gas phase to SO3 is -204 kJ/mol and for the oxidation of SO2 to SO3 is 89.5 kJ/mol. Find the enthalpy of formation of SO2 under these conditions.1282viewsTextbook QuestionGiven the standard heats of formation shown in Appendix B, what is ΔH° in kilojoules for the reaciton 3 N2O4(g) + 2 H2O(l) → 4 HNO3(aq) + 2 NO(g)649viewsTextbook QuestionWhen magnesium metal is burned in air (Figure 3.6), two products are produced. One is magnesium oxide, MgO. The other is the product of the reaction of Mg with molecular nitrogen, magnesium nitride. When water is added to magnesium nitride, it reacts to form magnesium oxide and ammonia gas. (e) The standard enthalpy of formation of solid magnesium nitride is -461.08 kJ>mol. Calculate the standard enthalpy change for the reaction between magnesium metal and ammonia gas.2039viewsTextbook QuestionCalcualte ΔH° in kilojoules for the synthesis of lime (CaO) from limestone (CaCO3), the key step in the manufacture of cement. CaCO3(s) → CaO(s) + CO2(g) ΔH°f [CaCO3(s)] = -1207.6 kJ/mol ΔH°f [CaO(s)] = -634.9 kJ/mol ΔH°f [CO2(g)] = -393.5 kJ/mol1490views1rankTextbook QuestionUse the information in Table 9.2 to calculate ΔH° in kilojoules for the photosynthesis of glucose (C6H12O6) and O2 from CO2 and liquid H2O, a reaciton carried out by all green plants1038views1rankTextbook QuestionUse the data in Appendix B to find standard enthalpies of reaction in kilojoules for the following processes: (c) Fe2O3 (s) + 3 CO (g) → Fe(s) + 3 CO2(g)327viewsTextbook QuestionUse the data in Appendix B to find standard enthalpies of reaction in kilojoules for the following processes: (b) 2 H2O2 (aq) → 2 H2O (l) + O2(g)786viewsTextbook QuestionUse the data in Appendix B to find standard enthalpies of reaction in kilojoules for the following processes: (a) C(s) + CO2(g) → 2 CO(g)693viewsTextbook QuestionIsooctane, C8H18, is the component of gasoline from which the term octane rating derives (b) The standard molar heat of combustion of isooctane (l) is -5461 kJ/mol. Calculate ΔH°f for isooctane(l)1936viewsTextbook QuestionThe mechanism for the oxidation of HBr by O2 to form 2 H2O and Br2 is shown in Exercise 14.74. (a) Calculate the overall standard enthalpy change for the reaction process.747viewsTextbook QuestionConsider the following acid-neutralization reactions involving the strong base NaOH(aq): HNO31aq2 + NaOH1aq2¡NaNO31aq2 + H2O1l2 HCl1aq2 + NaOH1aq2¡NaCl1aq2 + H2O1l2 NH4+1aq2 + NaOH1aq2¡NH31aq2 + Na+1aq2 + H2O1l2 (d) In the third equation NH4 +1aq2 is acting as an acid. Based on the value of H° for this reaction, do you think it is a strong or a weak acid? Explain.728viewsTextbook QuestionThe methane molecule, CH4, has the geometry shown in Figure 2.17. Imagine a hypothetical process in which the methane molecule is 'expanded,' by simultaneously extending all four C—H bonds to infinity. We then have the process CH41g2¡C1g2 + 4 H1g2 (a) Compare this process with the reverse of the reaction that represents the standard enthalpy of formation of CH41g2.771viewsTextbook QuestionOne of the best-selling light, or low-calorie, beers is 4.2% alcohol by volume and a 355-mL serving contains 110 Calories; remember: 1 Calorie = 1000 cal = 1 kcal. To estimate the percentage of Calories that comes from the alcohol, consider the following questions. (a) Write a balanced chemical equation for the reaction of ethanol, C2H5OH, with oxygen to make carbon dioxide and water. (b) Use enthalpies of formation in Appendix C to determine ΔH for this reaction. (c) If 4.2% of the total volume is ethanol and the density of ethanol is 0.789 g/mL, what mass of ethanol does a 355-mL serving of light beer contain? (d) How many Calories are released by the metabolism of ethanol, the reaction from part (a)? (e) What percentage of the 110 Calories comes from the ethanol?653viewsTextbook QuestionEmploying the bond enthalpy values listed in Table 8.4, estimate the molar enthalpy change occurring upon (c) formation of polyethylene terephthalate (PET).340viewsTextbook QuestionMetallic mercury is obtained by heating the mineral cinnabar (HgS) in air: HgS1s2 + O21g2 S Hg1l2 + SO21g2 (a) Use the data in Appendix B to calculate ΔH° in kilojoules for the reaction.710viewsTextbook QuestionMethanol 1CH3OH2 is made industrially in two steps from CO and H2. It is so cheap to make that it is being considered for use as a precursor to hydrocarbon fuels, such as methane 1CH42: Step 1. CO1g2 + 2 H21g2 S CH3OH1l2 ΔS° = - 332 J>K Step 2. CH3OH1l2 S CH41g2 + 1>2 O21g2 ΔS° = 162 J>K (f) Calculate ΔH° for step 2.363viewsTextbook QuestionMethanol 1CH3OH2 is made industrially in two steps from CO and H2. It is so cheap to make that it is being considered for use as a precursor to hydrocarbon fuels, such as methane 1CH42: Step 1. CO1g2 + 2 H21g2 S CH3OH1l2 ΔS° = - 332 J>K Step 2. CH3OH1l2 S CH41g2 + 1>2 O21g2 ΔS° = 162 J>K (a) Calculate ΔH° in kilojoules for step 1.452viewsTextbook QuestionSmall molecules with C'C double bonds, called monomers, can join with one another to form long chain molecules called polymers. Thus, acrylonitrile, H2C'CHCN, polymerizes under appropriate conditions to give polyacrylonitrile, a common starting material for producing the carbon fibers used in composites. (b) Use the bond dissociation energies in Table 7.1 to calculate ΔH per H2C'CHCN unit for the conversion of acrylonitrile to polyacrylonitrile. Is the reaction endothermic or exothermic?535viewsTextbook QuestionWhen a gaseous compound X containing only C, H, and O is burned in O2, 1 volume of the unknown gas reacts with 3 volumes of O2 to give 2 volumes of CO2 and 3 volumes of gaseous H2O. Assume all volumes are measured at the same temperature and pressure. (d) Combustion of 5.000 g of X releases 144.2 kJ heat. Look up ΔH°f values for CO21g2 and H2O1g2 in Appendix B, and calculate ΔH°f for compound X.491viewsTextbook QuestionCombustion analysis of 0.1500 g of methyl tert-butyl ether, an octane booster used in gasoline, gave 0.3744 g of CO2 and 0.1838 g of H2O. When a flask having a volume of 1.00 L was evacuated and then filled with methyl tertbutyl ether vapor at a pressure of 100.0 kPa and a temperature of 54.8 °C, the mass of the flask increased by 3.233 g. (d) The enthalpy of combustion for methyl tert-butyl ether is ΔH° combustion = -3368.7 kJ>mol. What is its standard enthalpy of enthalpy of formation, ΔH°f?389viewsTextbook QuestionAcid spills are often neutralized with sodium carbonate or sodium hydrogen carbonate. For neutralization of acetic acid, the unbalanced equations are 112 CH3CO2H1l2 + Na2CO31s2 S CH3CO2Na1aq2 + CO21g2 + H2O1l2 122 CH3CO2H1l2 + NaHCO31s2 CH3CO2Na1aq2 + CO21g2 + H2O1l2 (c) How much heat in kilojoules is absorbed or liberated in each reaction? See Appendix B for standard heats of for- mation; ΔH°f = - 726.1 kJ>mol for CH3CO2 Na(aq).635viewsTextbook Question(b) Use the data in Appendix B to calculate ΔH° for the reaction of potassium metal with water.1123viewsOpen QuestionCalculate the enthalpy of the reaction 2NO(g) + O2(g) → 2NO2(g) given the following reactions and enthalpies of formation: 12N2(g) + O2(g) → NO2(g), δH∘a=33.2 kJ 12N2(g) + 12O2(g) → NO(g), δH∘b=90.2 kJ601viewsOpen QuestionWhat is the isobaric heat of combustion for ethane, C2H6(g), in kJ per mole of ethane at 298.15 k?157viewsOpen QuestionHow much energy is required to decompose 765 g of PCl3162viewsOpen QuestionWhat is the heat of combustion of ethane, C2H6, in kilojoules per mole of ethane? Enthalpy of formation values can be found in this list of thermodynamic properties.164viewsOpen QuestionUse standard enthalpies of formation to calculate δh∘rxn for the following reaction: 2 H2S(g) + 3 O2(g)→ 2 H2O(l) + 2SO2(g)180viewsOpen QuestionCalculate the enthalpy of the reaction 2NO(g) + O2(g) → 2NO2(g)280viewsOpen QuestionUse the molar bond enthalpy data in the table to estimate the value of δ𝐻°rxn for the equation C2H4(g) + HBr(g) ⟶ C5H5Br(g)183viewsOpen QuestionUse standard enthalpies of formation to calculate δh∘rxn for the following reaction: Cao(s) + CO2(g) → CaCO3(s)171viewsOpen QuestionCalculate the enthalpy change for the reaction P4O6(s)+2 O2(g) → P4O10(s)198viewsOpen QuestionFor which one of the following is the enthalpy of the reaction the same as the enthalpy of formation?380viewsOpen QuestionUse the molar bond enthalpy data in the table to estimate the value of δ𝐻∘rxn for the equation377viewsOpen QuestionUse the values of δhf° in appendix 4 to calculate δh° for the following reactions.347viewsOpen QuestionFor which one of the following reactions is δh°rxn equal to the heat of formation of the product?353viewsOpen QuestionUse the standard reaction enthalpies given below to determine δh°rxn for the following reaction:430viewsOpen QuestionCalculate the heat evolved per mole on combustion of each substance to yield co2(g) and h2o(g).374viewsOpen QuestionCalculate δs∘rxn for the following reaction. the δs∘ for each species is shown below the reaction.307viewsOpen QuestionCalculate delta h for the following reaction254viewsOpen QuestionCalculate the enthalpy of the reaction 2NO(g) + O2(g) → 2NO2(g) given the following reactions and enthalpies of formation: 1/2N2(g) + O2(g) → NO2(g), ΔH∘a=33.2 kJ 1/2N2(g) + 1/2O2(g) → NO(g), ΔH∘b=90.2 kJ249viewsOpen QuestionUsing the table below, estimate δh for the "water splitting reaction": H2O(g) → H2(g) + 12 O2(g).218viewsOpen QuestionWhich answer best describes the transfer of heat that occurs when 1.20 mol of H2 reacts?146viewsOpen QuestionWhich answer best describes the transfer of heat that occurs when 1.70 mol of H2 reacts?150viewsOpen QuestionWhich answer best describes the transfer of heat that occurs when 1.40 mol of H2 reacts?141viewsOpen QuestionGiven the following at 25°C, calculate ΔHf for HCN(g) (in kJ/mol) at 25°C.172viewsOpen QuestionIn many ways, hydrogen as a biofuel compares very favorably to ethanol and other fuels.153viewsOpen QuestionWhich answer best describes the transfer of heat that occurs when 1.30 mol of H2 reacts?143viewsOpen Question4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g)214viewsOpen QuestionWhat is the change in enthalpy associated with the combustion of 530 g of methane (CH4)?217viewsOpen QuestionThe enthalpy of the reaction is –2,840 kJ. What is the heat of combustion, per mole, of glucose?144viewsShowing 97 of 97 practiceMore practice (0)
Textbook QuestionAtomic hydrogen (H) is used in welding (AHW). The atoms recombine to hydrogen molecules with a large release of heat according to the following reaction: 2 H1g2 ¡H21g2 (b) Which has the higher enthalpy under these conditions, 2 H1g2 or H21g2?585views
Textbook QuestionConsider the following equilibrium between oxides of nitrogen 3 NO(g) ⇌ NO2(g) + N2O(g) (a) Use data in Appendix C to calculate ΔH° for this reaction.461views
Textbook QuestionMethanol 1CH3OH2 can be made by the reaction of CO with H2: CO1g2 + 2 H21g2 Δ CH3OH1g2 (a) Use thermochemical data in Appendix C to calculate H for this reaction.1091views
Textbook QuestionAcetylene 1C2H21g22 is used for welding because oxyacetylene is the hottest burning common fuel gas. Using standard enthalpies of formation, calculate the quantity of heat produced when 10 g of acetylene is completely combusted in air under standard conditions.578views
Textbook QuestionThe fuel in high-efficiency natural-gas vehicles consists primarily of methane (CH4). (a) How much heat is produced in burning 1 mol of CH4(g) under standard conditions if reactants and products are brought to 298 K and H2O(l) is formed?518views
Textbook QuestionUsing values from Appendix C, calculate the value of H for each of the following reactions: (a) CaO(s) + 2 HF(g) → CaF2(s) + H2O(g)1060views
Textbook QuestionZinc metal reacts with hydrochloric acid according to the balanced equation: Zn(s) + 2 HCl(aq)¡ZnCl2(aq) + H2( g) When 0.103 g of Zn(s) is combined with enough HCl to make 50.0 mL of solution in a coffee-cup calorimeter, all of the zinc reacts, raising the temperature of the solution from 22.5 °C to 23.7 °C. Find ΔHrxn for this reaction as written. (Use 1.0 g>mL for the density of the solution and 4.18 J>g # °C as the specific heat capacity.)27027views
Textbook QuestionComplete combustion of 1 mol of acetone 1C3H6O2 liberates 1790 kJ: C3H6O1l2 + 4 O21g2 ¡ 3 CO21g2 + 3 H2O1l2 H° = -1790 kJ Using this information together with the standard enthalpies of formation of O21g2, CO21g2, and H2O1l2 from Appendix C, calculate the standard enthalpy of formation of acetone.2644views
Textbook QuestionCalcium carbide 1CaC22 reacts with water to form acetylene 1C2H22 and Ca1OH22. From the following enthalpy of reaction data and data in Appendix C, calculate Hf° for CaC21s2: CaC21s2 + 2 H2O1l2 ¡ Ca1OH221s2 + C2H21g2 H° = -127.2 kJ961views
Textbook QuestionGasoline is composed primarily of hydrocarbons, including many with eight carbon atoms, called octanes. One of the cleanest–burning octanes is a compound called 2,3,4- trimethylpentane, which has the following structural formula: The complete combustion of one mole of this compound to CO21g2 and H2O1g2 leads to H° = -5064.9 kJ. (b) By using the information in this problem and data in Table 5.3, calculate Hf° for 2,3,4-trimethylpentane.1186views
Textbook QuestionEthanol (C2H5OH) is blended with gasoline as an automobile fuel. (d) Calculate the mass of CO2 produced per kJ of heat emitted.727views
Textbook QuestionEthanol (C2H5OH) is blended with gasoline as an automobile fuel. (c) Calculate the heat produced per liter of ethanol by combustion of ethanol under constant pressure. Ethanol has a density of 0.789 g/mL.892views
Textbook QuestionMethanol 1CH3OH2 is used as a fuel in race cars. (b) Calculate the standard enthalpy change for the reaction, assuming H2O1g2 as a product.750views
Textbook QuestionHydrazine (N2H4) is a fuel used by some spacecraft. It is normally oxidized by N2O4 according to the equation: N2H4 (l) + N2O4 (g) → 2 N2O (g) + 2 H2O (g) Calculate ΔH°rxn for this reaction using standard enthalpies of formation.3797views1comments
Textbook QuestionPentane (C5H12) is a component of gasoline that burns according to the following balanced equation: C5H12(l ) + 8 O2( g)¡5 CO2( g) + 6 H2O( g) Calculate ΔH °rxn for this reaction using standard enthalpies of formation. (The standard enthalpy of formation of liquid pentane is -146.8 kJ>mol.)8448views3rank
Textbook QuestionUse standard enthalpies of formation to calculate ΔH °rxn for each reaction. d. Cr2O3(s) + 3 CO( g)¡2 Cr(s) + 3 CO2( g)1053views
Textbook QuestionUse standard enthalpies of formation to calculate ΔH °rxn for each reaction. c. 3 NO2( g) + H2O(l )¡2 HNO3(aq) + NO( g)1272views
Textbook QuestionUse standard enthalpies of formation to calculate ΔH °rxn for each reaction. a. C2H4( g) + H2( g)¡C2H6( g)992views
Textbook QuestionUse standard enthalpies of formation to calculate ΔH °rxn for each reaction. a. 2 H2S( g) + 3 O2( g)¡2 H2O(l ) + 2 SO2( g)387views
Textbook QuestionUse standard enthalpies of formation to calculate ΔH °rxn for each reaction. b. SO2( g) + 12 O2( g)¡SO3( g)1880views
Textbook QuestionEthanol (C2H5OH) can be made from the fermentation of crops and has been used as a fuel additive to gasoline. Write a balanced equation for the combustion of ethanol and calculate ΔH °rxn.1692views
Textbook QuestionTop fuel dragsters and funny cars burn nitromethane as fuel according to the balanced combustion equation: 2 CH3NO2(l ) + 32O2( g)¡2 CO2( g) + 3 H2O(l ) + N2( g) ΔH °rxn = -1418 kJ The enthalpy of combustion for nitromethane is -709.2 kJ>mol. Calculate the standard enthalpy of formation (ΔH °f ) for nitromethane.3091views3comments
Textbook QuestionThe explosive nitroglycerin (C3H5N3O9) decomposes rapidly upon ignition or sudden impact according to the balanced equation: 4 C3H5N3O9(l )¡12 CO2( g) + 10 H2O( g) + 6 N2( g) + O2( g) ΔH °rxn = -5678 kJ Calculate the standard enthalpy of formation (ΔH °f ) for nitroglycerin.6989views
Textbook QuestionMethanol (CH3OH) has been suggested as a fuel to replace gasoline. Find ΔH °rxn, and determine the mass of carbon dioxide emitted per kJ of heat produced. Use the information from the previous exercise to calculate the same quantity for octane, C8H18. How does methanol compare to octane with respect to global warming?1178views
Textbook QuestionAll the oxides of nitrogen have positive values of ΔGf° at 298 K, but only one common oxide of nitrogen has a positive ΔSf°. Identify that oxide of nitrogen without reference to thermodynamic data and explain.402views
Textbook QuestionThe standard enthalpies of formation of gaseous propyne (C3H4), propylene (C3H6), and propane (C3H8) are +185.4, +20.4, and -103.8 kJ/mol, respectively. (c) Which is the most efficient fuel in terms of heat evolved per unit mass?1912views
Textbook QuestionThe standard enthalpies of formation of gaseous propyne (C3H4), propylene (C3H6), and propane (C3H8) are +185.4, +20.4, and -103.8 kJ/mol, respectively. (b) Calculate the heat evolved on combustion of 1 kg of each substance.591views
Textbook QuestionIt is interesting to compare the 'fuel value' of a hydrocarbon in a hypothetical world where oxygen is not the combustion agent. The enthalpy of formation of CF4(g) is -679.9 kJ/mol. Which of the following two reactions is the more exothermic?CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g)CH4(g) + 4 F2(g) → CF4(g) + 4 HF(g)844views
Textbook QuestionUse standard enthalpies of formation to calculate the standard change in enthalpy for the melting of ice. (The ΔH °f for H2O(s) is -291.8 kJ/mol.)1839views
Textbook QuestionCalculate ∆H°f in kJ/mol for benzene, C6H6, from the following data: 2 C6H6(l) + 15 O2(g) → 12 CO2(g) + 6 H2O(l) ∆H°=-6534 kJ ∆H°f (CO2) = -393.5 kJ/mol ∆H°f(H2O) = -285.8 kJ/mol3429views1rank
Textbook QuestionAcetylene (C2H2) and nitrogen (N2) both contain a triple bond, but they differ greatly in their chemical properties. (b) By referring to Appendix C, look up the enthalpies of formation of acetylene and nitrogen. Which compound is more stable?329views
Textbook QuestionHydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. To compare the energy of these fuels to that of octane (C8H18), calculate the energy released per kilogram of octane.687views
Textbook QuestionHydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. Which fuel contains the most energy in the least mass?589views
Textbook QuestionAcetic acid (CH3CO2H), whose aqueous solutions are known as vinegar, is prepared by reaction of ethyl alcohol (CH3CH2OH) with oxygen: CH3CH2OH(l) + O2(g) → CH3CO2H(l) + H2O(l) Use the following data to calculate ∆H° in kilojoules for the reaction: ∆H°f [CH3CH2OH(l)] = -277.7 kJ/mol ∆H°f [CH3CO2H(l)] = -484.5 kJ/mol ∆H°f [H2O(l)] = -285.8 kJ/mol3155views
Textbook QuestionStyrene (C8H8), the precursor of polystyrene polymers, has a standard heat of combustion of -4395 kJ/mol. Write a balanced equation for the combustion reaction, and calculate ΔH°f for styrene in kJ/mol. ΔH°f [CO2(g)] = -393.5 kJ/mol; ΔH°f [H2O(l)] = -285.8 kJ/mol1114views
Textbook QuestionUnder certain nonstandard conditions, oxidation by O2( g) of 1 mol of SO2( g) to SO3( g) absorbs 89.5 kJ. The enthalpy of formation of SO3( g) is -204.2 kJ under these conditions. Find the enthalpy of formation of SO2( g).3218views
Textbook QuestionMethyl tert-butyl ether (MTBE), C5H12O, a gasoline additive used to boost octane ratings, has ΔH°f = -313.6 kJ/mol. Write a balanced equaiton for its combustion reaciton, and calcualte its standard heat of combustion in kilojoules1128views
Textbook QuestionMethyl tert-butyl ether (MTBE) is prepared by reaciton of methanol (l) (ΔH°f = -239.2 kJ/mol) with 2-methyl-propene (g), according to the requation Calculate ΔH°f in kJ/mol for 2-methylpropene714views
Textbook QuestionGiven the standard heats of formation shown in Appendix B, what is ΔH° in kilojoules for the reaciton CaCO3(s) → CaO(s) + CO2(g)?335views
Textbook QuestionThe ΔH for the oxidation of sulfur in the gas phase to SO3 is -204 kJ/mol and for the oxidation of SO2 to SO3 is 89.5 kJ/mol. Find the enthalpy of formation of SO2 under these conditions.1282views
Textbook QuestionGiven the standard heats of formation shown in Appendix B, what is ΔH° in kilojoules for the reaciton 3 N2O4(g) + 2 H2O(l) → 4 HNO3(aq) + 2 NO(g)649views
Textbook QuestionWhen magnesium metal is burned in air (Figure 3.6), two products are produced. One is magnesium oxide, MgO. The other is the product of the reaction of Mg with molecular nitrogen, magnesium nitride. When water is added to magnesium nitride, it reacts to form magnesium oxide and ammonia gas. (e) The standard enthalpy of formation of solid magnesium nitride is -461.08 kJ>mol. Calculate the standard enthalpy change for the reaction between magnesium metal and ammonia gas.2039views
Textbook QuestionCalcualte ΔH° in kilojoules for the synthesis of lime (CaO) from limestone (CaCO3), the key step in the manufacture of cement. CaCO3(s) → CaO(s) + CO2(g) ΔH°f [CaCO3(s)] = -1207.6 kJ/mol ΔH°f [CaO(s)] = -634.9 kJ/mol ΔH°f [CO2(g)] = -393.5 kJ/mol1490views1rank
Textbook QuestionUse the information in Table 9.2 to calculate ΔH° in kilojoules for the photosynthesis of glucose (C6H12O6) and O2 from CO2 and liquid H2O, a reaciton carried out by all green plants1038views1rank
Textbook QuestionUse the data in Appendix B to find standard enthalpies of reaction in kilojoules for the following processes: (c) Fe2O3 (s) + 3 CO (g) → Fe(s) + 3 CO2(g)327views
Textbook QuestionUse the data in Appendix B to find standard enthalpies of reaction in kilojoules for the following processes: (b) 2 H2O2 (aq) → 2 H2O (l) + O2(g)786views
Textbook QuestionUse the data in Appendix B to find standard enthalpies of reaction in kilojoules for the following processes: (a) C(s) + CO2(g) → 2 CO(g)693views
Textbook QuestionIsooctane, C8H18, is the component of gasoline from which the term octane rating derives (b) The standard molar heat of combustion of isooctane (l) is -5461 kJ/mol. Calculate ΔH°f for isooctane(l)1936views
Textbook QuestionThe mechanism for the oxidation of HBr by O2 to form 2 H2O and Br2 is shown in Exercise 14.74. (a) Calculate the overall standard enthalpy change for the reaction process.747views
Textbook QuestionConsider the following acid-neutralization reactions involving the strong base NaOH(aq): HNO31aq2 + NaOH1aq2¡NaNO31aq2 + H2O1l2 HCl1aq2 + NaOH1aq2¡NaCl1aq2 + H2O1l2 NH4+1aq2 + NaOH1aq2¡NH31aq2 + Na+1aq2 + H2O1l2 (d) In the third equation NH4 +1aq2 is acting as an acid. Based on the value of H° for this reaction, do you think it is a strong or a weak acid? Explain.728views
Textbook QuestionThe methane molecule, CH4, has the geometry shown in Figure 2.17. Imagine a hypothetical process in which the methane molecule is 'expanded,' by simultaneously extending all four C—H bonds to infinity. We then have the process CH41g2¡C1g2 + 4 H1g2 (a) Compare this process with the reverse of the reaction that represents the standard enthalpy of formation of CH41g2.771views
Textbook QuestionOne of the best-selling light, or low-calorie, beers is 4.2% alcohol by volume and a 355-mL serving contains 110 Calories; remember: 1 Calorie = 1000 cal = 1 kcal. To estimate the percentage of Calories that comes from the alcohol, consider the following questions. (a) Write a balanced chemical equation for the reaction of ethanol, C2H5OH, with oxygen to make carbon dioxide and water. (b) Use enthalpies of formation in Appendix C to determine ΔH for this reaction. (c) If 4.2% of the total volume is ethanol and the density of ethanol is 0.789 g/mL, what mass of ethanol does a 355-mL serving of light beer contain? (d) How many Calories are released by the metabolism of ethanol, the reaction from part (a)? (e) What percentage of the 110 Calories comes from the ethanol?653views
Textbook QuestionEmploying the bond enthalpy values listed in Table 8.4, estimate the molar enthalpy change occurring upon (c) formation of polyethylene terephthalate (PET).340views
Textbook QuestionMetallic mercury is obtained by heating the mineral cinnabar (HgS) in air: HgS1s2 + O21g2 S Hg1l2 + SO21g2 (a) Use the data in Appendix B to calculate ΔH° in kilojoules for the reaction.710views
Textbook QuestionMethanol 1CH3OH2 is made industrially in two steps from CO and H2. It is so cheap to make that it is being considered for use as a precursor to hydrocarbon fuels, such as methane 1CH42: Step 1. CO1g2 + 2 H21g2 S CH3OH1l2 ΔS° = - 332 J>K Step 2. CH3OH1l2 S CH41g2 + 1>2 O21g2 ΔS° = 162 J>K (f) Calculate ΔH° for step 2.363views
Textbook QuestionMethanol 1CH3OH2 is made industrially in two steps from CO and H2. It is so cheap to make that it is being considered for use as a precursor to hydrocarbon fuels, such as methane 1CH42: Step 1. CO1g2 + 2 H21g2 S CH3OH1l2 ΔS° = - 332 J>K Step 2. CH3OH1l2 S CH41g2 + 1>2 O21g2 ΔS° = 162 J>K (a) Calculate ΔH° in kilojoules for step 1.452views
Textbook QuestionSmall molecules with C'C double bonds, called monomers, can join with one another to form long chain molecules called polymers. Thus, acrylonitrile, H2C'CHCN, polymerizes under appropriate conditions to give polyacrylonitrile, a common starting material for producing the carbon fibers used in composites. (b) Use the bond dissociation energies in Table 7.1 to calculate ΔH per H2C'CHCN unit for the conversion of acrylonitrile to polyacrylonitrile. Is the reaction endothermic or exothermic?535views
Textbook QuestionWhen a gaseous compound X containing only C, H, and O is burned in O2, 1 volume of the unknown gas reacts with 3 volumes of O2 to give 2 volumes of CO2 and 3 volumes of gaseous H2O. Assume all volumes are measured at the same temperature and pressure. (d) Combustion of 5.000 g of X releases 144.2 kJ heat. Look up ΔH°f values for CO21g2 and H2O1g2 in Appendix B, and calculate ΔH°f for compound X.491views
Textbook QuestionCombustion analysis of 0.1500 g of methyl tert-butyl ether, an octane booster used in gasoline, gave 0.3744 g of CO2 and 0.1838 g of H2O. When a flask having a volume of 1.00 L was evacuated and then filled with methyl tertbutyl ether vapor at a pressure of 100.0 kPa and a temperature of 54.8 °C, the mass of the flask increased by 3.233 g. (d) The enthalpy of combustion for methyl tert-butyl ether is ΔH° combustion = -3368.7 kJ>mol. What is its standard enthalpy of enthalpy of formation, ΔH°f?389views
Textbook QuestionAcid spills are often neutralized with sodium carbonate or sodium hydrogen carbonate. For neutralization of acetic acid, the unbalanced equations are 112 CH3CO2H1l2 + Na2CO31s2 S CH3CO2Na1aq2 + CO21g2 + H2O1l2 122 CH3CO2H1l2 + NaHCO31s2 CH3CO2Na1aq2 + CO21g2 + H2O1l2 (c) How much heat in kilojoules is absorbed or liberated in each reaction? See Appendix B for standard heats of for- mation; ΔH°f = - 726.1 kJ>mol for CH3CO2 Na(aq).635views
Textbook Question(b) Use the data in Appendix B to calculate ΔH° for the reaction of potassium metal with water.1123views
Open QuestionCalculate the enthalpy of the reaction 2NO(g) + O2(g) → 2NO2(g) given the following reactions and enthalpies of formation: 12N2(g) + O2(g) → NO2(g), δH∘a=33.2 kJ 12N2(g) + 12O2(g) → NO(g), δH∘b=90.2 kJ601views
Open QuestionWhat is the isobaric heat of combustion for ethane, C2H6(g), in kJ per mole of ethane at 298.15 k?157views
Open QuestionWhat is the heat of combustion of ethane, C2H6, in kilojoules per mole of ethane? Enthalpy of formation values can be found in this list of thermodynamic properties.164views
Open QuestionUse standard enthalpies of formation to calculate δh∘rxn for the following reaction: 2 H2S(g) + 3 O2(g)→ 2 H2O(l) + 2SO2(g)180views
Open QuestionUse the molar bond enthalpy data in the table to estimate the value of δ𝐻°rxn for the equation C2H4(g) + HBr(g) ⟶ C5H5Br(g)183views
Open QuestionUse standard enthalpies of formation to calculate δh∘rxn for the following reaction: Cao(s) + CO2(g) → CaCO3(s)171views
Open QuestionFor which one of the following is the enthalpy of the reaction the same as the enthalpy of formation?380views
Open QuestionUse the molar bond enthalpy data in the table to estimate the value of δ𝐻∘rxn for the equation377views
Open QuestionUse the values of δhf° in appendix 4 to calculate δh° for the following reactions.347views
Open QuestionFor which one of the following reactions is δh°rxn equal to the heat of formation of the product?353views
Open QuestionUse the standard reaction enthalpies given below to determine δh°rxn for the following reaction:430views
Open QuestionCalculate the heat evolved per mole on combustion of each substance to yield co2(g) and h2o(g).374views
Open QuestionCalculate δs∘rxn for the following reaction. the δs∘ for each species is shown below the reaction.307views
Open QuestionCalculate the enthalpy of the reaction 2NO(g) + O2(g) → 2NO2(g) given the following reactions and enthalpies of formation: 1/2N2(g) + O2(g) → NO2(g), ΔH∘a=33.2 kJ 1/2N2(g) + 1/2O2(g) → NO(g), ΔH∘b=90.2 kJ249views
Open QuestionUsing the table below, estimate δh for the "water splitting reaction": H2O(g) → H2(g) + 12 O2(g).218views
Open QuestionWhich answer best describes the transfer of heat that occurs when 1.20 mol of H2 reacts?146views
Open QuestionWhich answer best describes the transfer of heat that occurs when 1.70 mol of H2 reacts?150views
Open QuestionWhich answer best describes the transfer of heat that occurs when 1.40 mol of H2 reacts?141views
Open QuestionIn many ways, hydrogen as a biofuel compares very favorably to ethanol and other fuels.153views
Open QuestionWhich answer best describes the transfer of heat that occurs when 1.30 mol of H2 reacts?143views
Open QuestionWhat is the change in enthalpy associated with the combustion of 530 g of methane (CH4)?217views
Open QuestionThe enthalpy of the reaction is –2,840 kJ. What is the heat of combustion, per mole, of glucose?144views