Enthalpy of Formation


by Physics197
Tags: enthalpy, formation
Physics197
Physics197 is offline
#1
Jan23-10, 03:11 PM
P: 74
1. The problem statement, all variables and given/known data

Using the enthalpies of formation given below, calculate ΔHrxn in kJ, for the following reaction.

3NO2(g)+1H2O(l) -> 2HNO3(g)+1NO(g)

NO2 (g): 33.10 kJ/mol
H2O (l): -285.83 kJ/mol
HNO3 (l): -174.10 kJ/mol
NO (g): 90.29 kJ/mol

2. Relevant equations

dHrxn = dHproducts - dHreactants

3. The attempt at a solution

Is this possible to do since the equation says HNO3 is a gas, but they give the enthalpy of formation for HNO3 as a liquid.
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physstudent1
physstudent1 is offline
#2
Jan26-10, 09:03 PM
P: 271
its possible but you need to use another enthalpy term that accounts for the latent heat which is from the phase transfer of liquid to gas
chemisttree
chemisttree is offline
#3
Jan27-10, 03:24 PM
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P: 3,725
That would be the Hvap of HNO3.


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