Sample Exercise 10.3 Calculating AH for Temperature and Phase Changes Calculate the total enthalpy change upon converting 1.00 mol of ice at -25 °C to water vapor (steam) at 125 °C under a constant pressure of 1 atm. The specific heats of ice, water, and steam are 2.03 J/g-K, 4.18 J/g-K, and 1.84 J/g-K, respectively. For H₂O, AHfus = 6.01 kJ/mol and AHVan = 40.67 kJ/mol. Format for AB. CD or FF:

9 080 LAB EXERCISE 11.D Testing A, Hᵒ from Formation Data The molar enthalpies of formation method was created earlier in this section from Hess' law. Both problem-solving methods are consistent with the law of conservation of energy. This lab exercise tests this new method against evidence gathered from calorimetry. Purpose The purpose of this problem is to test the use of molar enthalpies of formation as a method of predicting the enthalpy change of a reaction. Problem What is the standard molar enthalpy of combustion of methanol? Report Checklist O Purpose O Problem O Hypothesis ● Prediction O Design O Materials O Procedure O Evidence ● Analysis Evaluation (2, 3) Design Methanol is burned in excess oxygen in a special calorimeter. Assume that liquid water is produced. Evidence mass of methanol reacted = 4.38 g mass of water equivalent to calorimeter = 2.60 kg initial temperature of calorimeter = 20.4 °C final temperature of calorimeter = 27.9 °C (Note that the calorimeter has the…

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Question 20 10 pts 20. Calculate the change in internal energy (AE) for a system that is giving off 25.0 kJ of heat and is changing from 12.00 L to 6.00 L in volume at 1.50 atm pressure. (Remember that 101.3J = 1 Latm) +25.9 kJ ○ -16.0 kJ -25.9 kJ O-24.1 kJ +937 kJ