Question

Nitric acid, HNO3, was first prepared 1200 years ago by heating naturally occurring sodium nitrate (called saltpeter) with sulfuric acid to produce sodium bisulfate and collecting the vapors of HNO3 produced. Calculate ΔH°rxn for this reaction. ΔH°f[NaNO3(s)] = -467.8 kJ/mol; ΔH°f[NaHSO4(s)] = -1125.5 kJ/mol; ΔH°f[H2SO4(l)] = -814.0 kJ/mol; ΔH°f[HNO3(g)] = -135.1 kJ/mol.

Answer 1

In all of my years I have never heard of NaNO3 being referred to as saltpeter. KNO3 yes but not NaNO3. One web site where I looked just now lists EITHER NaNO3 or KNO3 (or other nitrates); another lists just KNO3. Just a side note.

NaNO3 + H2SO4 ==> NaHSO4 + HNO3

dHrxn = (n*dHf products) - (n*dHf reactants)