Thank you! The standard heat of formation, is defined as the enthalpy change for

Question

Thank you!

The standard heat of formation, is defined as the enthalpy change for the formation of one mole of substance from its constituent elements in their standard states. Thus, elements in their standard states have Ho : 0 Heat of formation values can be used to calculate the enthalpy change of any reaction PartA For which of the following reactions is Hrxn equal to of the product(s)? You do not need to look up any values to answer this question Check all that apply Consider, for example, the reaction View Available Hint(s) 2N0(g) + O2 (g)--2NO2 (g) with heat of formation values given by the following table Substance kJ/mol) NO(g)90.2 02(g) o NO2(g33.2 SO(g) (g)S02(g) S(s) + 02 (g) SO2 (g) 2Na(s) + F2 (g) 2NaE(s) Na(s)+F2(gNaF(s) Then the standard heat of reaction for the overall reaction is Na(s) + 2 (l)-NaF(s) ng,- 4'(products)- r(reactants) Submit 200.2) + 2(33.2) 114 kJ

Explanation / Answer

Ans :

part A :

when the reaction involves the formation of one mole of products from its constituent elements present in standard states , the enthalpy associated with the reaction is called as enthalpy of formation.

So here we have two reactions where Hrxn = Hf :

S (s) + O2 (g) = SO2 (g)

Na (s) + 1/2 F2 (g) = NaF (s)

Ans 2 :

The enthlpy of combustion of pentane can be calculated by the subtraction of the formation enthalpies of reactants from those of products .

So here :

5(-393.5) + 6(-241.8) - (-119.9) - 8(0)

= -3057 KJ

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.