Concept explainers
Interpretation:
The
Concept introduction:
Bond enthalpy:
The measure of stability of molecule is bond enthalpy. The change in enthalpy is related in breaking a specific bond of 1 mole of gaseous molecule. In solids and liquids bond enthalpies are affected by neighboring molecules. There is possibility to predict the enthalpy of reaction using the average bond enthalpies. Energy is always needed for the breaking of
The enthalpy of reaction in gas phase is given by,
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Check out a sample textbook solutionChapter 9 Solutions
Student Solutions Manual for Ebbing/Gammon's General Chemistry
- Bond 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_forwardUsing the standard enthalpy of formation data in Appendix G, calculate the bond energy of the carbon-sulfur double bond in CS2.arrow_forwardWrite all resonance structures of chlorobenzene, C6H5Cl, a molecule with the same cyclic structure as benzene. In all structures, keep the CCl bond as a single bond. Which resonance structures are the most important?arrow_forward
- A commercial process for preparing ethanol (ethyl alcohol), C2H5OH, consists of passing ethylene gas. C2H4, and steam over an acid catalyst (to speed up the reaction). The gas-phase reaction is Use bond enthalpies (Table 9.5) to estimate the enthalpy change for this reaction when 37.0 g of ethyl alcohol is produced.arrow_forwardUsing the bond dissociation enthalpies in Table 8.8, estimate the enthalpy of combustion of gaseous methane, CH4, to give water vapor and carbon dioxide gas.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
- Explain the decomposition of nitroglycerin in terms of relative bond enthalpies.arrow_forwardCompare your answers from parts a and b of Exercise 69 of Chapter 3 with H values calculated for each reaction using standard enthalpies of formation in Appendix 4. Do enthalpy changes calculated from bond energies give a reasonable estimate of the actual values?arrow_forwardUse average bond energies together with the standard enthalpy of formation of C( g) (718.4 kJ/mol) to estimate the standard enthalpy of formation of gaseous benzene, C6H6( g). (Remember that average bond energies apply to the gas phase only.) Compare the value you obtain using average bond energies to the actual standard enthalpy of formation of gaseous benzene,82.9 kJ/mol. What does the difference between these two values tell you about the stability of benzene?arrow_forward
- Using average bond enthalpies (linked above), estimate the enthalpy change for the following reaction: CH4(g) + Cl₂(g)→→→→CH3CI(g) + HCI(g) kJarrow_forwardUsing average bond enthalpies (linked above), estimate the enthalpy change for the following reaction: 2co(g) + 2NO(g)→2C02(g) + N2(g) kJarrow_forwardCalculate the enthalpy change (ΔH(rxn)) of the following reaction using the bond energies above. Draw the correct Lewis structures to determine the bonding structure. Calculate reactant energy – product energy for your final answer. H2 (g) + CO2 (g) → H2O (g) + CO (g)arrow_forward
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