The molar heat of formation of nh4no3 (s) is -367.54 kj and those of no2(g) is 81.46and h2o(l) is -285.78 kj at 298k and 1.0 atmospheric pressure .Calculate delta  H and delta U for the reaction.

Dear Student,

The molar heat of formation of NH4NO3 = -367.54 kJ

 The molar heat of formation of N2O = 81.46 kJ

 The molar heat of formation of H2O = -285.78 kJ

The chemical reaction of formation of NH4NO3 is as follow:

N2O + 2H2O  →  NH4NO3

Enthalpy of reaction = ΔHf (NH4NO3) - [ΔHf (N2O) + 2 ΔHf(H2O)]

Enthalpy of reaction =  -367.54 - [81.46 + 2×(-285.78)]

Enthalpy of reaction = -367.54 - [81.46 -571.56]

Enthalpy of reaction = ΔH = -367.54 + 490.10

Enthalpy of reaction = ΔH =122.56 kJ = 122560 J

As we know that,

ΔH =  ΔU + (Δn) RT

(Δn) = 1-3 = -2

R= 8.314 JK-1 mol-1

T = 298 K

Putting all the values in the relation:

122560 = ΔU +(-2) × 8.314 ×298

ΔU = 122560 + 16.628 ×298

ΔU = 127515.14 J

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equation is wrong

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nt able 2 understand a single bit....

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