Home
Class 12
CHEMISTRY
The enthalpy of formation of enthane and...

The enthalpy of formation of enthane and benzene from the gaseous atoms are `-2839.2` and `-5506 kJ//mol` respectively. Bond enthalpy of `C = C` bond is
Given: Resonance energy of benzene `=-23.68" kJ/mol"`
Bond enthalpy of `C-H` bond `=411.0" kJ/mol"`

Text Solution

Verified by Experts

` 2 C(g) + 6 H(g) to C_(2) H_(6) Delta H^(@) = -2839.2`
`C_(2) H_(6) to 2 C(g) + 6 H(g) Delta H^(@) = 2839.2 `
`sum C- C + 6 sum C - H = 2839.2 Delta H^(@) = 2839.2`
`sum C - C + 6 xx 410 . 87 = 2839.2 `
`implies sum C - C = 373. 98 " " ... (1)`
` 2 C (g) + 4 H(g) to C_(2) H_(4) (g) " " Delta H^(@) =-2275.2`
`C_(2) H_(4) to 2 C (g) + 4 H(g) Delta H^(@) = 2275.2`
`sum C = C + 4 sum C - H = 2275.2`
`sum (C = C) = 631.72 " " .... (2)`
`6 C (g) + 6 H (g) to C_(6) H_(6) Delta H^(@) = -5506`
`implies C_(6) H_(6) to 6 C (g) + 6 H (g) " " DeltaH^(@) = 5506`
`implies 3 sum C = C + 3 sum C - C + 6 sum C - H + x = 5506`
Putting all the values from `eq^(n)` , 1 , & (2) we get x = 23.68
`implies ` Resonance energy of benzene
`=-23.68 ` kJ/mole
Promotional Banner

Topper's Solved these Questions

  • THERMOCHEMISTRY

    MOTION|Exercise EXERCISE -1 SECTION - A|5 Videos

  • THERMOCHEMISTRY

    MOTION|Exercise EXERCISE -1 SECTION - B|9 Videos

  • SURFACE CHEMISTRY

    MOTION|Exercise Exercise - 3 (Level-II)|12 Videos

  • THERMODYNAMICS

    MOTION|Exercise EXERCISE - 4 (LEVEL - II)|19 Videos

Similar Questions

Explore conceptually related problems

The heat of dissociation of benzene in isolated gaseous atoms is 5335 kJ/mol . The bond enthalpies C-C, C = C and C - H bonds are 347.3, 615 and 416.2 kJ respectively. Magnitude of resonance energy of benzene is

The bond energies of C=C and C-C at 298 K are 590 and 331 kJ mol^(-1) , respectively. The enthalpy of polymerisation per mole of ethaylene is

Enthalpy of polymerisation of ehtylene, as represented by the reaction , nCH_(2)=CH_(2)rarr(-CH_(2)-CH_(2)-) is -100 kJ per mole of ehtylene. Given bond enthalpy of C=C bond is 600 kJ mol^(-1) , enthalpy of C-C bond ( in kJ mol) will be:

Find the enthalpy of formation of hydrogen flouride on the basis of following data: Bond energy of H-H bond =434 kJ mol^(-1) Bond energy of F-F bond =158 kJ mol^(-1) Bond enegry of H -F bond =565 kJ mol^(-1)