In a constant-pressure calorimetry experiment, Jiwon and Jisun dissolved 10.0 g of CaCl2 (MM = 110.98 g mol-1) in 250.0 g of water initially at 20.00°C. As the solid dissolves in water, the temperature rises to 26.73°C. Calculate the enthalpy of dissolution (ΔHdissolution) of CaCl2 in kJ mol-1. Assume that the calorimeter absorbed a negligible amount of heat.

(b) (i) Mixtures of molten salts often result in high excess mixing enthalpies. Calorimetric experiments of a 25:75 mixture of NaCl and KCl revealed an enthalpy of mixing ΔmixH of -0.4095 kJ mol-1 . Calculate β for this mixture. (ii) Aluminium boils at 2737 K at 100.0 kPa pressure. Given that at 100.0 kPa the molar heat capacity (Cp) of liquid aluminium is 29.30 J K-1 mol-1 , and of aluminium gas is 20.79 J K-1 mol-1 , calculate the total entropy change for the reaction: Al(liquid, 2000 K) → Al (gas, 3500 K). ΔvapS = 49.24 J K-1 mol-1

Assume you are interested in exploring the use of ammonium nitrate (NH4NO3) as the active ingredient in an inexpensive home-made cold pack. You decide that a practical cold pack should be able to depress the temperature of 1 kg of human muscle tissue by 5 oC. Now you need to know the amount of NH4NO3 required to achieve this. Ammonium nitrate is a highly water soluble solid. You believe the enthalpy of dissolution  for NH4NO3 must be determined. To this end, you add 2.339 g of NH4NO3 to 99.7 mL of water at 23.7 °C in a constant-pressure calorimeter and close the calorimeter. The temperature of the water decreases to a minimum of 21.9 °C 1) The specific heat of human muscle tissue (smuscle) is 3.47 kJ/kg oC. Given this value, how many grams of ammonium nitrate (NH4NO3) is required to depress the temperature of 1.00 kg of human muscle by 5.00 oC? Please remember, show all work in a legible, highly organized manner

Element X has an enthalpy of fusion (ΔfusH°) of 59.2 kJ mol-1 at its melting point (Tm = 684°C). Calculate ΔSsys for the freezing process,X(l) ⇌ X(s)at 1 bar and 684°C. Express your answer in units of J mol-1 K-1 to 3 significant figures.