Apparent and partial molar heat capacities and volumes of aqueous HClO 4 and HNO 3 from 10 to 55 °C

Apparent molar heat capacities and volumes of aqueous solutions containing HClO 4 and HNO 3 have been determined from 10 to 55 °C. The temperature dependences of the standard state heat capacities and volumes of ClO 4 − (aq) and NO 3 − (aq) from 10 to 55 °C were found to be well represented by the following equations:[Formula: see text]Combination of the experimental results with semiempirical equations for ion–solvent interaction has led to predictions of the standard state volumes and heat capacities for these ionic species at higher temperatures. Keywords: heat capacities, volumes, nitric acid, perchloric acid.