Home
Class 12
CHEMISTRY
Find DeltaH of the following reaction: ...

Find `DeltaH` of the following reaction:
`OF_(2)(g) +H_(2)O(g) rarr O_(2)(g)+2HF (g)`, average bond energies of `O -F, O-H, O =O`, and `H - F` are `44,111, 118`, and `135 kcal mol^(-1)`, respectively.

Text Solution

Verified by Experts

`OF_(2)(g)+H_(2)O(g)rarr O_(2)(g)+2HF(g) " " , " " Delta_(r )H=?`
(i) Bond Breaking : (endothermic) : `Delta_(r )H_(1)`
`F-O-F(g)rarr O(g)+2F(g) " " , Delta_(r )H=+2xx44 " "` [bond energy of O - F = 44]
`H-O-H(g)rarr O(g)+2H(g)" " , Delta_(r )H=+2xx111 " "` [bond energy of O - H = 111]
`rArr Delta_(r )H_(1)=2xx44+2xx111=+310` kcal.
(ii) Bond Formation : (exothermic) : `Delta_(r )H_(2)`
`O(g)+O(g)rarrO=O(g) " " , Delta_(r )H=-118 " "` [bond energy of O = O = 118]
`2[H(g)+F(g)rarr H-F(g)] " " , Delta_(r )H=-2xx135 " "` [bond energy of H - F = 270]
`rArr Delta_(r )H_(2)=-118+(-2xx135)=-388` kcal
Now using Hess' Law , `Delta_(r )H=Delta_(r )H_(1)+Delta_(r )H_(2)=310+(-388)=-78` kcal
Promotional Banner

Topper's Solved these Questions

  • CHEMICAL THERMODYNAMICS

    VMC MODULES ENGLISH|Exercise SOLVED EXAMPLES|19 Videos

  • CHEMICAL THERMODYNAMICS

    VMC MODULES ENGLISH|Exercise PRACTICE EXERCISE|22 Videos

  • CHEMICAL KINETICS

    VMC MODULES ENGLISH|Exercise JEE Advanced (Archive)|52 Videos

  • CLASSIFICATION OF ELEMENTS AND PERIODICITY IN PROPERTIES

    VMC MODULES ENGLISH|Exercise JEE ADVANCE (ARCHIVE)|30 Videos

Similar Questions

Explore conceptually related problems

Calculate the enthalpy change for the reaction H_2(g) + 1/2 O_2(g) to H_2O (g) if the bond energies of H - H,O = O and O - H bonds are 104, 118 and 11 kcal mol^(-1) respectivley.

Calculate the standard enegry change for the reaction: OF_(2)(g) +H_(2)O(g) rarr O_(2)(g) +2HF(g) at 298K The standard enthalpies of formation of OF_(2)(g), H_(2)O(g) , and HF(g) are +20, -250 , and -270 kJ mol^(-1) , respectively.

Calculate the enthalpy change (Delta H) of the following reaction 2C_(2)H_(2)(g)+5O_(2)(g)rarr4CO_(2)(g)+2H_(2)O(g) given average bond enthalpies of various bonds, i.e., C-H,C-=C,O=O,C=O,O-H as 414,814,499,724 and 640 kJ mol^(-1) respectively.

In the reaction 2H_(2)(g) + O_(2)(g) rarr 2H_(2)O (l), " "Delta H = - xkJ

DeltaH for the reaction, OF_(2)+H_(2)OrarrO_(2)+2HF (B.E. of O-F, O-H, H-F and O=O are 44, 111, 135 and "119 kcal mol"^(-1) respectively)

Calculate heat of the following reaction at constant pressure, F_(2)O(g)+H_(2)O(g)rarrO_(2)(g)+2HF(g) The heats of formation of F_(2)O(g),H_(2)O(g) and HF(g) are 5.5 kcal-57kcal and -64 kcal repectively.

In the reaction, CO_(2)(g)+H_(2)(g)toCO(g)+H_(2)O(g)," "DeltaH=2.8 kJ DeltaH represents :

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 the standard enthalpy change (in kJ "mol"^(-1) ) for the reaction H_(2)(g)+O_(2)(g)toH_(2)O_(2)(g) , given that bond enthalpy of H-H, O=O,O-H and O-O (in kJ "mol"^(-1) ) are respectively 438, 498, 464 and 138.

For the reaction C_(3)H_(8)(g)+5O_(2)(g)rarr3CO_(2)(g)+4H_(2)O(l) at constant temperature, DeltaH-DeltaU is