Concept explainers
Interpretation:
The enthalpy change of formation of
Concept introduction:
The amount of energy required to break a particular bond in one mole of gas molecules is known as bond enthalpy.
Bond enthalpy is directly proportional to the strength of the bond. Higher the bond enthalpy, stronger is the bond.
The breaking of bonds always leads to absorption of energy.
Formation of bonds always leads to release of energy.
The strength of a bond is determined using the values of bond enthalpy.
The process of breaking a bond involves the change of state of the system from higher stability to lower stability, due to which it always requires external energy for its initiation.
The process of formation of a bond involves the change of state of the system from lower stability to higher stability due to which it involves the release of energy
Want to see the full answer?
Check out a sample textbook solutionChapter 8 Solutions
Chemistry
- The reaction of quicklime, CaO, with water produces slaked lime, Ca(OH)2, which is widely used in the construction industry to make mortar and plaster. The reaction of quicklime and water is highly exothermic: CaO(s)+H2O(l)Ca(OH)2(s)H=350kJmol1 (a) What is the enthalpy of reaction per gram of quicklime that reacts?. (b) How much heat, in kilojoules, is associated with the production of 1 ton of slaked lime?arrow_forwardGiven the following data calculate H for the reaction On the basis of the enthalpy change, is this a useful reaction for the synthesis of ammonia?arrow_forwardEstimate H for the following reactions using bond energies given in Table 8.5. 3CH2=CH2(g) + 3H2(g) 3CH2CH3(g) The enthalpies of formation for C6H6(g) and C6H12 (g) are 82.9 and 90.3 kJ/mol. respectively. Calculate H for the two reactions using standard enthalpies of formation from Appendix 4. Account for any differences between the results obtained from the two methods.arrow_forward
- The equation for the fermentation of glucose to alcohol and carbon dioxide is: C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g) The enthalpy change for the reaction is 67 kJ. Is this reaction exothermic or endothermic? Is energy, in the form of heat, absorbed or evolved as the reaction occurs?arrow_forwardUsing the standard enthalpy of formation data in Appendix G, calculate the bond energy of the carbon-sulfur double bond in CS2.arrow_forwardBond Enthalpy When atoms of the hypothetical element X are placed together, they rapidly undergo reaction to form the X2 molecule: X(g)+X(g)X2(g) a Would you predict that this reaction is exothermic or endothermic? Explain. b Is the bond enthalpy of X2 a positive or a negative quantity? Why? c Suppose H for the reaction is 500 kJ/mol. Estimate the bond enthalpy of the X2 molecule. d Another hypothetical molecular compound, Y2(g), has a bond enthalpy of 750 kJ/mol, and the molecular compound XY(g) has a bond enthalpy of 1500 kJ/mol. Using bond enthalpy information, calculate H for the following reaction. X2(g)+Y2(g)2XY(g) e Given the following information, as well as the information previously presented, predict whether or not the hypothetical ionic compound AX is likely to form. In this compound, A forms the A+ cation, and X forms the X anion. Be sure to justify your answer. Reaction: A(g)+12X2(g)AX(s)The first ionization energy of A(g) is 400 kJ/mol. The electron affinity of X(g) is 525 kJ/mol. The lattice energy of AX(s) is 100 kJ/mol. f If you predicted that no ionic compound would form from the reaction in Part e, what minimum amount of AX(s) lattice energy might lead to compound formation?arrow_forward
- Use bond energies to estimate E for the combustion of one mole of acetylene: C2H2(g)+52O2(g)2CO2(g)+H2O(g)arrow_forwardNitrogen monoxide, a gas recently found to be involved in a wide range of biological processes, reacts with oxygen to give brown NO2 gas. 2 NO(g) + O2(g) NO2(g)rH = 114.1 kJ/mol-rxn Is this reaction endothermic or exothermic? What is the enthalpy change if 1.25 g of NO is converted completely to NO2?arrow_forwardFor the reactions of molecular hydrogen with fluorine and with chlorine: (a) Calculate the enthalpy change for breaking all the bonds in the reactants. (b) Calculate the enthalpy change for forming all the bonds in the products. (c) From the results in parts (a) and (b), calculate the enthalpy change for the reaction. (d) Which reaction is most exothermic?arrow_forward
- The enthalpy change for the reaction of hydrogen gas with fluorine gas (o produce hydrogen fluoride is 542 U for the equation as written: mg src=Images/HTML_99425-10-41QAP_image001.jpg alt="" align="top"/> l type='a'> What is the enthalpy change per mole of hydrogen fluoride produced? Is the reaction exothermic or endothermic as written? What would be the enthalpy change for the reverse of the given equation (that 1%, for the decomposition of HF into its constituent elements)?arrow_forwardGiven the following data: NO2(g) NO(g) + O(g)H = 233 kJ 2O3(g) 3O2(g)H = 427 kJ NO(g) + O3(g) NO2(g) + O2(g)H = 199 kJ Calculate the bond energy for the O2 bond, that is, calculate H for: O2(g) 2O(g)H = ?arrow_forwardHydrogen, H2, is prepared by steam reforming, in which hydrocarbons are reacted with steam. For CH4, CH4(g)+H2O(g)CO(g)+3H2(g) Calculate the enthalpy change H for this reaction, using standard enthalpies of formation.arrow_forward
- Chemistry by OpenStax (2015-05-04)ChemistryISBN:9781938168390Author:Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark BlaserPublisher:OpenStaxChemistry: Principles and PracticeChemistryISBN:9780534420123Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward MercerPublisher:Cengage LearningChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage Learning
- Chemistry: An Atoms First ApproachChemistryISBN:9781305079243Author:Steven S. Zumdahl, Susan A. ZumdahlPublisher:Cengage LearningGeneral Chemistry - Standalone book (MindTap Cour...ChemistryISBN:9781305580343Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; DarrellPublisher:Cengage Learning