Enthalpy of Formation

  1. 1. The problem statement, all variables and given/known data

    Using the enthalpies of formation given below, calculate ΔH°rxn 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.
  2. jcsd
  3. 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
  4. chemisttree

    chemisttree 3,717
    Science Advisor
    Homework Helper
    Gold Member

    That would be the Hvap of HNO3.
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