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Enthalpy of Formation Solutions Library

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Enthalpy of Formation

Q. Calculate the standard enthalpy of the reaction, ΔH°rxn, for the thermite reaction:2Al(s) + Fe2O3(s) → 2Fe(s) + Al2O3(s)Elements in their standard ...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Consider the exothermic reaction2 C2H6(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(g)Calculate the standard heat of reaction, or ΔH°rxn, for this reaction usin...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. The decomposition of NI3 to form N2 and I2 releases − 290.0 kJ of energy. The reaction can be represented as2NI3(s) → N2(g) + 3I2(g), ΔHrxn = − 290...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Part B. The combustion of heptane, C7H16, occurs via the reactionC7H16 (g) + 11 O2(g) → 7 CO2(g) + 8 H2O(g)with heat of formation values given by t...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Part A. For which of the following reactions is ΔH°rxn equal to ΔH°f of the product(s)? You do not need to look up any values to answer this questi...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Part D. The answer is part C is the energy required to break six carbon-carbon bonds in benzene. Calculate the average bond enthalpy of one carbon-...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Calculate the mass of glucose metabolized by an 89.5 kg person in climbing a mountain with an elevation gain of 1350 m. Assume that the work perfor...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Part A. What is the standard enthalpy change for the reaction that represents breaking all the bonds in gaseous benzene, C6H6(g)? Express your answ...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. For the reaction given in Part A, how much heat is absorbed when 3.60 mol of A reacts?Express your answer to three significant figures and include ...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Calculate the standard enthalpy change for the reaction2A + B ⇌ 2C + 2DUse the following data:Express your answer to three significant figures and ...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Suppose that 0.290 mol of methane, CH4(g), is reacted with 0.440 mol of fluorine, F2(g), forming CF4(g) and HF(g) as sole products. Assuming that t...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Calculate the enthalpy change, ΔH°, for the reverse of the formation of methane:CH4(g) → C(s) + 2 H2(g)Express your answer to one decimal place and...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Calculate the enthalpy change, ΔH°, for the "expansion" of methane:CH4(g) → C(g) + 4 H(g)Express your answer to one decimal place and include the a...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Compare the reaction for the "expansion" of methane with the reverse of the reaction that represents the standard enthalpy of formation. Which prop...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Consider the reactionMg(OH)2(s) → MgO(s) + H2O(l)with enthalpy of reaction ΔH°rxn = 37.5 kJ/mol. What is the enthalpy of formation of MgO(s)?Expres...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Determine the enthalpy for this reaction:MgCl2(s) + 2 NaOH(aq) → Mg(OH)2(s) + 2 NaCl(aq)Express your answer in kilojoules per mole to one decimal p...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. What is the balanced chemical equation for the reaction used to calculate ΔH°f of BaCO3(s)?If fractional coefficients are required, enter them as a...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. What is ΔH°rxn for the following chemical reaction? H2O(l) + CCl4(l) → COCl2(g) + 2 HCl(g) You can use the following table of standard heats of for...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Part C. Methane, when liquefied, has a density of 0.466 g/ mL, the density of methanol is 0.791 g/ mL at 25°C. Calculate the enthalpy of combustion...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Part B. Calculate the standard enthalpy changes for the combustion of a mole of methane and the combustion of a mole of methanol.Enter the enthalpy...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Repeat the procedure from Part C for the other three oxides,then rank all four oxides according to their enthalpy of reduction.Metals often react w...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Consider the data in the following table:Calculate ΔH° rxn for the reduction for V2O5.Metals often react with oxygen to produce ionic oxides such a...

Solved • Jul 2, 2020

Enthalpy of Formation

Q. Part C. Use average bond enthalpies to estimate the enthalpy ΔHrxn of the following reaction: 2SF4 (g) + O2 (g) → 2OSF4 (g) Express your answer num...

Solved • Jun 30, 2020

Enthalpy of Formation

Q. If the heat of formation of H2O(l) is -286 kJ/mol, which of the following thermochemical equations for the formation of H2O is correct?  a) H2 (g) ...

Solved • Jun 30, 2020

Enthalpy of Formation

Q. Write the chemical equation for the reaction whose enthalpy change is the standard enthalpy of formation of sucrose (table sugar (C12H22O11)Express...

Solved • Jun 30, 2020

Enthalpy of Formation

Q. What is the value of the standard enthalpy of formation of an element in its most stable form?

Solved • Jun 30, 2020

Enthalpy of Formation

Q. Consider the two diagrams below.Based on (ii), write an equation relating ΔHZ to the other enthalpy changes in the diagram.

Solved • Jun 30, 2020

Enthalpy of Formation

Q. Consider the two diagrams below.Based on (i), write an equation showing how ΔHA is related to ΔHB and ΔHC.

Solved • Jun 30, 2020

Enthalpy of Formation

Q. The complete combustion of ethanol, C2H5OH (FW = 46.0 g/mol), proceeds as follows: C2H5OH(l) + 3 O2 (g) → 2 CO2 (g) + 3 H2O(l) ΔH = − 555 kJ What i...

Solved • Jun 30, 2020

Enthalpy of Formation

Q. Find  ΔH°f for C2H5OH(l) from the given table.Express your answer using one decimal place.

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Enter an equation for the formation of C2H5OH(l) from its elements in their standard states. Enter any reference to carbon as C(s).Express your ans...

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Find ΔH°f for C2H4(g) from the given table.Express your answer using one decimal place.

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Enter an equation for the formation of C2H4(g) from its elements in their standard states. Enter any reference to carbon as C(s).  Express your ans...

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Find ΔH for MgCO3 from the given table.Express your answer using one decimal place.

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Enter an equation for the formation of MgCO3(s) from its elements in their standard states. Enter any reference to carbon as {\rm C}({\rm s}).Expre...

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Find ΔH°f for BF3(g) from the given table.SubstanceΔH°f kJ/molB(g)565.0B(s)0F(g)79.38F2(g)0BF3(g)-1136.0BCl3(g)-403.8B­2H6(g)36.4B2O3(g)-1273.5Expr...

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Enter an equation for the formation of BF3  from its elements in their standard states.Express your answer as a chemical equation. Identify all of ...

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Calculate the standard enthalpy of combustion. The standard enthalpy of formation of sucrose is -2226.1 kJ/mol.

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Calculate the standard enthalpy of combustion. The standard enthalpy of formation of palmitic acid -208 kJ/mol. Express your answer using four sign...

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Dry ice is solid carbon dioxide. Instead of melting, solid carbon dioxide sublimes according to the following equation: CO2 (s) → CO2 (g). When dry...

Solved • Jun 25, 2020

Enthalpy of Formation

Q. Identify a substance that is NOT in its standard state. a. HCl(s) b. N2(g) c. Rn(g) d. F2(g) e. Li(s)

Solved • Jun 15, 2020

Enthalpy of Formation

Q. The enthalpy for the formation of 1 mole of NH3(aq) is -80.29 kJ/mol. What is the ΔHf for the formation of 3 moles of NH3(aq)?

Solved • May 1, 2020

Enthalpy of Formation

Q. The overall enthalpy change for a reaction _____.a. can only be determined by making calorimetric measurements.b. depends only on the amount of mat...

Solved • Apr 28, 2020

Enthalpy of Formation

Q. The combustion of acetone is C3H6O(l) + 4O2(g) → 3CO2(g) + 3 H2O(g)                ΔH rxnIf a bottle of nail polish remover contains 152 g of aceto...

Solved • Apr 28, 2020

Enthalpy of Formation

Q. Calculate ΔH°rxn for the reduction of V2O5. The table is : V2O5(s) = -1550.6 ΔH° kJ/mol : H2(g) = 0 ΔH° kJ/mol : V(s) = 0 ΔH° kJ/mol: H2O(g) -241.8...

Solved • Apr 28, 2020

Enthalpy of Formation

Q. Which of the following substances have a standard heat of formation (ΔHf°) of zero? Cl2(g) at 2 atm ,C2H6(g) at standard conditions ,O2(g) at 25.0 ...

Solved • Apr 27, 2020

Enthalpy of Formation

Q. Consider the reactionNa2CO3(s)→Na2O(s)+CO2(g)with the enthalpy of reactionΔH°rxn = 321.5 kJ/molWhat is the enthalpy of formation of Na2O(s)?Express...

Solved • Apr 27, 2020

Enthalpy of Formation

Q. Determine the enthalpy for this reaction:2 NaOH(s) +CO2(g) → Na2CO3(s) + H2O(l)

Solved • Apr 27, 2020

Enthalpy of Formation

Q. Using values from Appendix C, calculate the value of ΔH° for each of the following reactions.4 NH3(g) + O2(g) → 2 N2H4(g) + 2 H2O(l)Express your an...

Solved • Apr 23, 2020

Enthalpy of Formation

Q. Using values from Appendix C, calculate the value of ΔH° for each of the following reactions.2 CuO(s) + NO(g) → Cu2O(s) + NO2(g)Express your answer...

Solved • Apr 23, 2020

Enthalpy of Formation

Q. Using values from Appendix C, calculate the value of ΔH° for each of the following reactions.4 FeO(s) + O2(g) → 2 Fe2O3(s)Express your answer using...

Solved • Apr 23, 2020

Enthalpy of Formation

Q. Using values from Appendix C, calculate the value of ΔH° for each of the following reactions.CaO(s) + 2 HCl(g) →CaCl2(s) + H2O(g)Express your answe...

Solved • Apr 23, 2020

Enthalpy of Formation

Q. Calculate the approximate enthalpy change, ΔH°, for the combustion of methane: CH4 + 2O2 ⇌ 2H2O + CO2 Use the values you calculated in Parts A to D...

Solved • Apr 20, 2020

Enthalpy of Formation

Q. For each of the following reactions, identify another quantity that is equal to Δ°Hrxn. 1. CH4(g) + 2O2(g) →CO2(g) + 2H2O(l) a) enathalpy of combus...

Solved • Mar 25, 2020

Enthalpy of Formation

Q. Calculate ΔH° for each of the following reactions, which occur in the atmosphere.(a) C2H4(g) + O3(g) → CH3CHO(g) + O2(g)(b) O3(g) + O(g) → 2 O2(g)

Solved • Mar 25, 2020

Enthalpy of Formation

Q. Calculate ΔH° for each of the following reactions, which occur in the atmosphere.(a) O3(g) + NO(g) → NO2(g) + O2(g)(b) SO3(g) + H2O(l) → H2SO4(aq)

Solved • Mar 25, 2020

Enthalpy of Formation

Q. A hypothetical solution forms between a solid and a liquid. The values of the thermodynamic quantities involved in the process are shown in the fol...

Solved • Mar 17, 2020

Enthalpy of Formation

Q. Estimate ΔH°rxn for the following reaction, using the chemical reactions given above and the ΔH°rxn values you calculated in part (a). Show all wor...

Solved • Dec 19, 2019

Enthalpy of Formation

Q. Estimate the enthalpy of reaction, ΔH rxn°, for each of the following reactions using the information provided. Show all work and circle your final...

Solved • Dec 19, 2019

Enthalpy of Formation

Q. Estimate the enthalpy of reaction, ΔH rxn°, for each of the following reactions using the information provided. Show all work and circle your final...

Solved • Dec 19, 2019

Enthalpy of Formation

Q. Estimate the enthalpy of reaction, ΔH rxn°, for each of the following reactions using the information provided. Show all work and circle your final...

Solved • Dec 19, 2019

Enthalpy of Formation

Q. Gaseous hydrogen and fluorine combine in the reaction below to form hydrogen fluoride:H2(g) + F2(g) → 2 HF(g)        ΔH°rxn = -540 kJWhat is the va...

Solved • Nov 25, 2019

Enthalpy of Formation

Q. The ΔHf° for CO2 (g) is -393 kJ/mole and ΔHrxn for the reaction2CO(g) + O2(g) → 2CO2(g) is -560 kJ. The ΔHf° for CO(g) is (in kJ/mole):(a) +113 (b)...

Solved • Oct 18, 2019

Enthalpy of Formation

Q. For the reaction,2H2 (g) + O2 (g) → 2H2O(g) ΔH = -484 kJwhich of the following is true?(a) The ΔHf° for H2O(g) is -484 kJ/mole.(b) All reactants an...

Solved • Oct 18, 2019

Enthalpy of Formation

Q. What is ΔHrxn at 25C?ΔHf ° (H+) = 0.0 kJ/mol;ΔHf ° (OH-) = -230.0 kJ/mol;ΔHf ° (H2O) = -285.8 kJ/mol)H+ (aq) + OH- (aq) → H2O (l)A. -55.8 J/mol B. ...

Solved • Oct 9, 2019

Enthalpy of Formation

Q. For which of the following reactions is the value of ∆H°rxn equal to ∆H°f for the product?I. N2(g) + O3(g) ⟶ N2O3(g)II. 2 Ca(s) + O2(g) ⟶ 2 CaO(s)I...

Solved • Oct 3, 2019

Enthalpy of Formation

Q. Pentaborane B5H9(s) burns vigorously in O2 to give B2O3(s) and H2O(l):2 B5H9(s) + 12 O2(g) ⟶5 B2O3(s) + 9 H2O(l)The standard enthalpy change for th...

Solved • Oct 3, 2019

Enthalpy of Formation

Q. Given the data in the table below, ΔH°rxn for the following reaction is __________ kJ.3NO2(g) + H2O(l) → 2HNO3 (aq) + NO (g)A) 64B) 140C) -140D) -5...

Solved • Sep 24, 2019

Enthalpy of Formation

Q. For which one of the following equations is ΔH°rxn equal to ΔHf° for the product?A) Xe(g) + 2F2(g) → XeF4 (g)B) CH4(g) + 2Cl2(g) → CH2Cl2(l) + 2HCl...

Solved • Sep 24, 2019

Enthalpy of Formation

Q. The value of ΔH° for the reaction below is +128.1 kJ:CH3OH(l) → CO(g) + 2H2(g)How many kJ of heat are consumed when 5.10 g of CO(g) is formed as sh...

Solved • Sep 24, 2019

Enthalpy of Formation

Q. Consider the following reaction:2Mg(s) + O2(g)→ 2MgO(s)        ΔH = -1204 kJWhich of the following statements is true?a) This reaction is endotherm...

Solved • Sep 15, 2019

Enthalpy of Formation

Q. Given the data in the table on the right, the ΔH°rxn for the reaction:Ca(OH)2 + 2 H3AsO4 → Ca(H2AsO4)2 + 2 H2O  is ___________ kJ.A. -744.9B. -4519...

Solved • Sep 13, 2019

Enthalpy of Formation

Q. The value of ΔH° for the reaction below is -790 kJ. The enthalpy change accompanying the reaction of 0.95 g of S is __________ kJ.                 ...

Solved • Sep 13, 2019

Enthalpy of Formation

Q. Calculate the enthalpy change (ΔH) for the following reaction:H2(g) + F2(g) = 2HF

Solved • Aug 25, 2019

Enthalpy of Formation

Q. For which of the following reactions is ΔH°rxn equal to ΔH°f of the product(s)?2Na(s) + Cl2(g) → 2NaCl(s)H2(g) + 12O2(g) → H2O(g)Na(s) + 12Cl2(g) →...

Solved • Aug 7, 2019

Enthalpy of Formation

Q. What is ΔHrxn° for the following chemical reaction? CS2(g) + 2H2O(l) → CO2(g) + 2H2S(g) You can use the following table of standard heats of format...

Solved • Aug 6, 2019

Enthalpy of Formation

Q. Use the information in the table to calculate ΔH° in kilojoules for the photosynthesis of glucose (C6H12O6) and O2 from CO2 and liquid H2O, a react...

Solved • Aug 6, 2019

Enthalpy of Formation

Q. Part A. Calculate the enthalpy change, delta H, for the expansion of methaneCH4(g) → C(g) + 4H(g)Part B. Calculate the enthalpy change, delta H for...

Solved • Jul 10, 2019

Enthalpy of Formation

Q. The standard enthalpy of combustion of naphthalene is -5157 kJ/mol. Calculate its standard enthalpy of formation.The reaction for the combustion of...

Solved • Jul 9, 2019

Enthalpy of Formation

Q. The fuel in high-efficiency natural gas vehicles consists primarily of methane CH4.How much heat is produced in burning 6 mol of CH4 under standard...

Solved • Jan 3, 2019

Enthalpy of Formation

Q. Consider the following equilibrium between oxides of nitrogen: 3NO(g) ⇌ NO2(g) + N2O(g)Use data in Appendix C in the textbook to calculate ΔH˚ for ...

Solved • Dec 11, 2018

Enthalpy of Formation

Q. Methanol (CH3OH) can be made by the reaction of CO with H2: CO(g) + 2 H2(g) ⇌ CH3OH(g)Use thermochemical data in Appendix C in the textbook to calc...

Solved • Dec 11, 2018

Enthalpy of Formation

Q. Acetylene (C2H2) and nitrogen (N2) both contain a triple bond, but they differ greatly in their chemical properties.Both N2 and C2H2 possess triple...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Acetylene (C2H2) and nitrogen (N2) both contain a triple bond, but they differ greatly in their chemical properties.Calculate the enthalpy of oxida...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Estimate ΔH for the atomization of benzene, C6H6: C6H6(g) → 6 C(g) + 6 H(g), by using ΔH˚f data (ΔH˚f (C, g) = 718.4 kJ/mol, ΔH˚f (H, g) = 217.94 k...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. The stratospheric ozone (O3) layer helps to protect us from harmful ultraviolet radiation. It does so by absorbing ultraviolet light and falling ap...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Consider the decomposition of liquid hydrogen peroxide (H2O2) to form water and oxygen.What is the heat of formation for hydrogen peroxide?

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Consider the decomposition of liquid hydrogen peroxide (H2O2) to form water and oxygen.What is the heat of formation for liquid water?

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Consider the decomposition of liquid hydrogen peroxide (H2O2) to form water and oxygen.What is the heat of formation for gaseous oxygen?

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Consider the decomposition of liquid hydrogen peroxide (H2O2) to form water and oxygen. Write the balanced chemical equation that corresponds to th...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Consider the decomposition of liquid hydrogen peroxide (H2O2) to form water and oxygen. Write the balanced chemical equation that corresponds to th...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Consider the decomposition of liquid hydrogen peroxide (H2O2) to form water and oxygen. Write the balanced chemical equation that corresponds to th...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Dry chemical hand warmers utilize the oxidation of iron to form iron oxide according to the following reaction: 4 Fe(s) + 3O2(g) → 2Fe2O3(s)Standar...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Dry chemical hand warmers utilize the oxidation of iron to form iron oxide according to the following reaction: 4 Fe(s) + 3O2(g) → 2Fe2O3(s)Standar...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Standard thermodynamic quantities for selected substances at 25 °C SubstanceΔH ( kJ/mol)Na(s)0.0Na(g)107.5Cl(g)121.3Cl2(g)0.0NaCl(s)-411.2Pb(s)0.0P...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Standard thermodynamic quantities for selected substances at 25 °C SubstanceΔH ( kJ/mol)Na(s)0.0Na(g)107.5Cl(g)121.3Cl2(g)0.0NaCl(s)-411.2Pb(s)0.0P...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Standard thermodynamic quantities for selected substances at 25 °C SubstanceΔH ( kJ/mol)Na(s)0.0Na(g)107.5Cl(g)121.3Cl2(g)0.0NaCl(s)-411.2Pb(s)0.0P...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Standard thermodynamic quantities for selected substances at 25 °C SubstanceΔHf ( kJ/mol)Na(s)0.0Na(g)107.5Cl(g)121.3Cl2(g)0.0NaCl(s)-411.2Pb(s)0.0...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. Standard Enthalpies (or Heats) of Formation, ΔH°f , at 298 KSubstanceΔH°f (kJ/mol)Na(s)0.0Na(g)107.5Cl(g)121.3Cl2(g)0.0NaCl(s)-411.2Pb(s)0.0Pb(g)19...

Solved • Nov 12, 2018

Enthalpy of Formation

Q. The thermite reaction, in which powdered aluminum reacts with iron oxide, is highly exothermic:2Al(s) + Fe2O3(s) → Fe(s) + 2Al2O3(s)Use standard en...

Solved • Nov 12, 2018