Concept explainers
Interpretation:
The average bond enthalpy of the
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.
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CHEMISTRY- BUNDLE CONNECT PLUS ACCESS
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- Estimate 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_forwardWith a platinum catalyst, ammonia will burn in oxygen to give nitric oxide, NO. 4NH3(g)+5O2(g)4NO(g)+6H2O(g);H=906kJ What is the enthalpy change for the following reaction? NO(g)+32H2O(g)NH3(g)+34O2(g)arrow_forwardhat is the enthalpy change for a process? Is enthalpy a state function? In what experimental apparatus are enthalpy changes measured?arrow_forward
- 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_forwardThe thermochemical equation for the burning of methane, the main component of natural gas, is CH4(g)+2O2(g)CO2(g)+2H2O(l)H=890kJ (a) Is this reaction endothermic or exothermic? (b) What quantities of reactants and products are assumed if H = 890 kJ? (c) What is the enthalpy change when 1.00 g methane burns in an excess of oxygen?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_forward
- Given 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_forwardA 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_forward
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