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The First Law of Thermodynamics AE=q+w The 1st Law of Thermodynamics (6) says that the change in the internal energy of a system is dependent on 1) the system exchanging heat with the surroundings and 2) the system either doing work on the surroundings or the surroundings doing work on the system.
Exercises C. Consider the reaction of aluminum metal with hydrochloric acid. 2 Al(s) + 6 HCl(aq) → 2 AICI3(aq) + 3 H₂(g) When 5.00 g of aluminum is added to an excess of hydrochloric acid, all at a constant pressure of 1 atm and a constant temperature of 298 K, the system expels 99.8 kJ of heat into the surroundings. Calculate the number of moles of hydrogen gas that are produced. Assume that the heat is exchanged without a change in temperature. Use equations 6 (from Model 3), 4 (from Question 7a), and 2 (from Model 2) to calculate the amount of work done by the system when the hydrogen gas expands against a constant-pressure atmosphere of 1 atm at 298 K. (Use R = 8.314 x 10³ kJ mol-¹ K-¹.) Use the sign conventions of heat and work and the First Law of Thermodynamics (equation 6 in Model 3) to calculate the change in internal energy of the system.