PART - 1 CH - 4 Chemical Bonding and Molecular Structure — Chemistry STD 11 Science — Question
Gujarat BoardEnglish MediumSTD 11 ScienceChemistryPART - 1 CH - 4 Chemical Bonding and Molecular Structure2 Marks
Question
What do you meant by bond enthalpy? In polyatomic molecules in which way it can be calculated?
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Answer
Bond enthalpy : The energy required to break one mole of specific bonds between two atoms in gaseous state is called bond enthalpy. Its unit is $kJ mol ^{-1}$. $ H_{2(g)} \longrightarrow H_{(g)}+H_{(g)} \quad \Delta_{a} H^{\ominus}=435.8 kJ mol^{-1} $ Polyatomic molecules like $H _2 O$ have two $- O - H$ bonds but the value of their bond enthalpy is different. Hence average bond enthalpy is used is them. Average bond enthalpy $ =\frac{\text { Total bond dissociation enthalpy }}{\text { No. of bonds of same type }} $
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