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The enthalpy changes at 298K in success...

The enthalpy changes at 298K in successive breaking of `O-H` bonds of water are
`H_(2)O(g) to H(g)+OH(g) , DeltaH=498kJ " mol"^(-1)`
`OH(g) to H(g)+O(g) , DeltaH=428kJ" mol"^(-1)`
The bond enthalpy of `O-H` bond is:

Text Solution

Verified by Experts

The correct Answer is:
463
Bond energy is the average energy required to break each bond of the same type in compund.
`Delta H_(av) = (498 + 428)/(2) = 462" kJ mol"^(-1)`
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The enthalpy changes at 298 K in successive breaking of O-H bonds of water, are H_(2)O(g) rarr H(g)+OH(g),DeltaH=498kJ mol^(-1) OH(g) rarr H(g)+O(g), DeltaH =428 kJ mol^(-1) The bond energy of the O-H bond is

H_2(g) + 1/2 O_2(g) to H_2O (l), DeltaH = - 286 kJ 2H_2(g) + O_2(g) to 2H_2O (l), DeltaH = …kJ

The enthalpy of vaporisation of liquid water using the data H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(l) , DeltaH=-285.77 kJ//mol H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(g) , DeltaH=-241.84 kJ//mol

The H - O - O bond angle in H_(2)O_(2) (g) is

H_(2)(g) +(1)/(2)O_(2)(g) rarr H_(2)O(g) DeltaH =- 242 kJ mol^(-1) Bond energy of H_(2) and O_(2) is 436 and 500 kJ mol^(-1) , respectively. What is bond energy of O-H bond?

Calculate enthalpy of formation of methane (CH_4) from the following data : (i) C(s) + O_(2)(g) to CO_(2) (g) , Delta_rH^(@) = -393.5 KJ mol^(-1) (ii) H_2(g) + 1/2 O_(2)(g) to H_(2)O(l) , Deta_r H^(@) = -285.5 kJ mol^(-1) (iii) CH_(4)(g) + 2O_(2)(g) to CO_(2)(g) + 2H_(2)O(l), Delta_(r)H^(@) = -890.3 kJ mol^(-1) .

The average O-H bond energy in H_(2)O with the help of following data. (1) H_(2)O(l)rarrH_(2)O(g), Delta H= +40.6 kJ mol^(-1) (2) 2H(g)rarrH_(2)(g), DeltaH= -435.kJ mol^(-1) (3) O_(2)(g)rarr2O(g), Delta H= +489.6 kJ mol^(-1) (4) 2H_(2)(g)+O_(2)(g)rarr2H_(2)O(l), Delta H= -571.6 kJ mol^(-1)

The bond energies of H - H and I - I bonds are 435 kJ mol^-1 and 150 kJ mol^-1 respectively. If DeltaH_f^o for HI is 26.5 kJ mol^-1 then bond enthalpy of H-I bond is

The enthalpy of the reaction H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(g) is DeltaH_(1) and that of H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(l) is DeltaH_(2) . Then

Knowledge Check

  • Dissociation of water takes place in two steps : H_(2)OrarrH+OH," "DeltaH=+497.8kJ OH rarr H+O," "DeltaH=428.5kJ Water is the bond energy of O-H bond ?

    A
    `"463.15 kJ mol"^(-1)`
    B
    `"428.5 kJ mol"^(-1)`
    C
    `"69.3 kJ mol"^(-1)`
    D
    `"926.3 kJ mol"^(-1)`