I am currently doing a lab report on Hess\' law and have the following question

Question

I am currently doing a lab report on Hess' law and have the following question as part of the lab report to answer

5. Use the thermodynamic quantities given below to calculate the theoretical H for this reaction:

   NH3+ HCl NH4Cl

H°f for NH3(aq) = - 80.29 kJ/mol

H°f for HCl (aq) = - 167.2 kJ/mol

H°f for NH4+(aq) = - 132.5 kJ/mol

H°f for Cl-(aq) = - 167.2 kJ/mol

Could someone point me in the direction of how to work this out? This may help me figure out if I've calculated the results from my experiment correctly

Explanation / Answer

The given reaction is:

NH3 (aq)+ HCl (aq) NH4Cl (aq)

this can also be written as:

1NH3(aq) + 1HCl(aq) ---> 1NH4+(aq) + 1Cl-(aq)

Ho rxn = 1*Hof(NH4+(aq)) + 1*Hof(Cl-(aq)) - 1*Hof( NH3(aq)) - 1*Hof(HCl(aq))

Ho rxn = 1*(-132.5) + 1*(-167.2) - 1*(-80.29) - 1*(-167.2)

Ho rxn = -52.21 KJ/mol

Answer: -52.21 KJ/mol

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