Average bond enthalpy table

Use average bond enthalpies (Table 8.4) to estimate AH for the atomization of benzene,... 

This is a good way of estimating the reactions enthalpy of a large number of reaction using a relatively small table of average bond enthalpies. Table 2.4 lists some average bond enthalpies. With this table the reaction enthalpies of a large number of reactions can be estimated. 

Table 2.2 Average Bond Lengths (A) and Average Bond Enthalpies (kJ mol 1) of Some Important Covalent Bonds"...

STRATEGY Decide which bonds are broken and which bonds are formed. Use the average bond enthalpies in Table 6.7 to calculate the decrease in... 

The bond enthalpy in NO is 632 kj-mol-1 and that of each N-O bond in N02 is 469 kj-mol-1. Using Lewis structures and the average bond enthalpies given in Table 6.7, explain (a) the difference in bond enthalpies between the two molecules (b) the fact that the bond enthalpies of the two bonds in N02 are the same. 

It must be remembered that mathematically bonds formed give a negative value and bonds broken give a positive value. To make use of this approach, bond enthalpies are needed, and Table 4.1 shows average bond enthalpies for numerous kinds of bonds. 

A second CFC used as a refrigerant and in aerosols (besides that discussed in Example 12.8) is CCI3F. Use the atomization enthalpies and average bond enthalpies from Table 12.3 to estimate the standard enthalpy of formation (AH°) of this compound in the gas phase. 

Propane has the structure IT3C—CH2—CH3. Use average bond enthalpies from Table 12.3 to estimate the change in enthalpy AH° for the reaction... 

The experimental value is -484 kJ, which is in closer agreement with the estimated value than ordinarily expected. Since Table 2.8 contains average bond enthalpies, there is frequently a small error when comparing estimates to a specific reaction. 

Using the data in Table A-V, calculate the average bond enthalpy of the oxygen-oxygen bond in ozone. 

In the problem, we are given AH° for the reaction, and we can look up the 0=0 bond enthalpy in Table 9.4 of the text. Solving for the average bond enthalpy in ozone,... 

The bond dissociation enthalpies of bonds such as C-H, C-Cl, C=0, N=N and O-H are approximately the same in different molecules. If the values of bond dissociation enthalpy for a bond between two atoms (A and B) in several different molecules are averaged, the resulting value is called the mean bond enthalpy (Table 13.4). Mean bond enthalpies are useful in estimating enthalpy changes for reactions for which standard enthalpies of formation are unavailable, but the fact that such values may have been obtained by averaging bond dissociation enthalpies from different types of molecule may lead to substantial errors in the calculated value of AH. ... 

Use the average bond enthalpies listed in Table 13.4 to calculate the standard enthalpy of formation of benzene -assume that the atoms are arranged according to the Kekul structure... 

Just as we can define an average bond enthalpy, we can also define an average bond length for a number of common bonds (A TABLE 8.5). Of particular interest is the relationship, in any atom pair, among bond enthalpy, bond length, and number of bonds between the atoms. For example, we can use data in Tables 8.4 and 8.5 to compare the bond lengths and bond enthalpies of carbon-carbon single, double, and triple bonds ... 

Use average bond enthalpies from Table 8.4 to estimate the enthalpies of the following gas-phase reactions ... 

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