Sodium acetate is used in many hot packs, which rely on the ability of sodium acetate trihydrate (SAT) to become supercooled, and then spontaneously crystallize via an exothermic process. A solution is made from 50.0 grams of SAT dissolved in 50.0 g of water heated above the melting point of SAT, and is slowly supercooled below room temperature, to 16°C. Assume the specific heat capacity of SAT is 2.19 J/g ·°C and the specific heat capacity of water is 4.184 J/g-°c. The molar enthalpy of fusion is 35.9 kJ/mol for SAT and its molar mass is 136.08 g/mol. Upon crystallization, the temperature increases from 16.0 °C to the melting point of SAT. What is the final temperature of the SAT?

Consider the following phase change equilibrium: CHCl3(s)= CHCl3(l) If delta H* is 9.74 kJ/mol and delta S* is 40.00 J/mol K, determine the melting point of CHCl3 in K?

What is the total enthalpy change during the process in which 100.0 g of water at 50.0 °C is cooled to ice at -30.0 °C ? (Assume P = 1.0 atm). Note: COOLING is an EXOTHERMIC PROCESS!!! AH WILL BE NEGATIVE! Solution S.H. water = 4.18 J/g °C Temperature AHfus = 6.01 kJ/mol 50.0 °C 0.0 °C 1 -30.0 °C 2 3 S.H. ice = 2.03 J/g °C 100.0 g H₂O = 5.552 mol H₂O 18.01 g/mol ΔΗ, = SH x Υ x ΔΤ AH₁ = (4.18 J/g °C)(100.0 g)(0.0 - 50.0 °C) == - 20900 J - 20.9 kJ Energy (J) Thus the total enthalpy change is: AH₂ = -AHfus XY AH₂ = -(6.01 kJ/mol)(5.552 mol) = -33.4 kJ ΔΗ, = SH x Υ x ΔΤ AH3 = (2.03 J/g °C)(100.0 g)(- 30.0 - 0.00 °C) = 6090 J = - 6.09 kJ -20.9 kJ-33.4 kJ - 6.09 kJ = - 60.4 kJ

A liquid at 20.0 °C exhibits a vapor pressure of 0.555 atm. The liquid is heated to 60.0 °C. What is the new vapor pressure (in atm to three decimal places) if ΔHvap = 25.595 kJ mol–1?

What is the resulting temperature when 100 g of water at 75°C is mixed with 30 g of ice at 0 °C? Assume that all of the ice has melted. The specific heat of water is 4.184 J g-1 C°.-1 and the heat of fusion of ice is 335 J g-1.

A 2.82 kg cast iron pan is heated to some temperature, T;, and subsequently quenched in 3.5 gallons (approximately 13.25 L) of mineral oil at 21.2 °C to harden the cast iron. The system reaches an equilibrium temperature of 74.4 °C. What was the initial temperature (in °C) of cast iron pan? (Cs,iron = 0.460 J g°C; cs.oil = 1.67 J g-1 °C-1; doil = 0.850 g mL) %3D A: 846

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How much heat, in joules and in calories, must be added to a 89.1 g chromium block with a specific heat of 0.450 J/g·°C to increase its temperature from 25°C to its melting temperature of 1907°C?

If 100.0 g of ice at -10.0°C is placed in 200. g of water at 90.0°C in an insulated container, what will be the temperature of the system when equilibrium is established? (Sp. heat of H2O(s) = 2.09 J/g-oC, Sp. heat of H2O(l) = 4.18 J/g-°C, heat of fus. of H2O(s) = 333 J/g.

A: 4.91 g of LiCl was dissolved in 50.0 mL of water in the same calorimeter as in problem 1. Analysis of the thermogram showed the initial temperature to be 22.9°C, the final temperature to be 49.2°C. Was the dissolution of the ionic solid exothermic or endothermic?   B: Using the information above, calculate the mass of the water.   C: Calculate ΔHsolution   D : Calculate the standard molar enthalpy of solution. Assume that the pressure is 1 bar.