Heat capacities of NaNO3 and KNO3 from 350 to 800 K

Abstract The heat capacities of NaNO3 and KNO3 were determined from 350 to 800 K by differential scanning calorimetry. Solid-solid transitions and melting were observed at 550 and 583 K for NaNO3 and 406 and 612 K for KNO3, respectively. The entropies associated with the solid-solid transitions were measured to be (8.43± 0.25) J K−1 mole−1 for NaNO3 and (13.8±0.4) J K−1 mole−1 for KNO3. At 298.15 K the values of C0P S0P, {H0(T)-H0(0)}/T and -{G0(T)-H0(0)}/T, respectively, are 91.94, 116.3, 57.73, and 58.55 J K−1 mole−1 for NaNO3 and 95.39, 133.0, 62.93, and 70.02 J K−1 mole−1 for KNO3. Values for S0T, {H0(T)-H0(0)}/T, and -{G0(T)-H0(0)}/T were calculated and tabulated from 15 to 800 K for NaNO3 and KNO3.