Which of the following equation gives th...

Which of the following equation gives the values of heat of formation `(DeltaH_(f)^(@))`?

C(diamond) ` + O_(2)(g) rarr CO_(2)(g)`

`(1)/(2) H_(2)(g) + (1)/(2)F_(2)(g) rarr HF (g)`

`N_(2)(g) + 3H_(2)(g) rarr 2NH_(3)(g)`

`H_(2)(g) + F_(2)(g) rarr 3HF(g)`

Text Solution

Verified by Experts

The correct Answer is:

The amount of heat either evoved or absorbed when one gram mole of a substance is formed from its constituent elements, is known as the standard heat of formation `(DeltaH_(f)^(@))`.
Standard state temperature os `25C^(@)` or `298K` and pressure of gaseous substance heat of formation of HF.
`(1)/(2) H_(2)(g) + (1)/(2)F_(2)(g) rarr HF (g), DeltaH_(f)^(@) = ?` (Standard heat of formation of HF (g))

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Which of the following equations express DeltaH as heat of combustion ?

`H_(2)(g)+I_(2)to2HI(g)`

`CaCO_(3)(s)toCaO(s)+CO_(2)(g)`

`CH_(4)(g)+2O_(2)(g)toCO_(2)(g)+2H_(2)O(l)`

`2KCIO_(3)(s)to2KCI(s)+3O_(2)(g)`

Which of the following equations respresents standard heat of formation of CH_(4) ?

`C_(("diamond"))+2H_(2(g))rarr CH_(4(g))`

`(C_(("graphite"))+2H_(2(g))rarr CH_(4(g))`

`(C_(("diamond"))+4H_((g))rarr CH_(4(g))`

`C_(("graphite"))+4H_((g))rarr CH_(4(g))`

Which of the following does not represent heat of formation (Delta H_f^@) ?

`C_("graphite") + O_(2)(g) to CO_(2)(g)`

`H_(2)(g) + 1/2O_(2)(g) to H_(2)O(l)`

`2CO(g) + O_(2)(g) to 2CO_(2)(g)`

All of these