HEAT-CAPACITY OF HYDROFLUORIC-ACID AND (HYDROFLUORIC-ACID PLUS 2-METHYLPROPANE) BY TEMPERATURE-PULSE CALORIMETRY

Heat capacities of anhydrous liquid hydrofluoric acid and of HF satura ted with 2-methylpropane are reported. The heat capacity of slightly c ompressed liquid HF is (2.66 and 2.80) J . g(-1). K-1 at (25.1 and 45. 9) degrees C, respectively. The heat capacity of liquid HF slightly co mpressed and saturated at 24 degrees C with 2-methylpropane (3.7 mass %) is 2.58 J . g(-1). K-1 at 24.3 degrees C. Accuracy is within 2%. Th ese are the first available data for the heat capacity of liquid HF ab ove its normal boiling point. A temperature-pulse calorimeter is descr ibed.