Series of Systems/Heat/Work Questions

jeudi 10 juillet 2014

I am trying to fully grasp the concepts behind the series of questions here.



"You're baking a batch of shepard's pie in your oven and fall asleep while it's baking. When you are awakened by the fire alarm, you quickly clear out the smoke and open the oven. Your shepard's pie is reduced to ash. Within the tragic scenario of destroying your pie, would the oven be considered part of the system or is it the surroundings? (Write system or surroundings)"



My Answer: Surroundings.

Why? Because the oven is not part of the molecular environment.



"Based upon your answer in question 28, is the ashing of the pie an exothermic or endothermic process?"

My answer: Endothermic

Why? Endothermic means that heat is being absorbed here. The outside surrounding (oven) with its heat is adding to the molecular "pie."



"Your kitchen is an anomaly in that it always maintains atmospheric pressure. If your raw shepard's pie occupied 2.55L of space and released 622L of gas as it burned, what amount of work was done under these conditions? (1 L*atm = 101.325J)."

This is where I am struggling big time. There seems to be many different equations here and I am not sure what equation to begin with. I see I need to find work done, but I don't understand how this translates to gas and the numbers given. Any guidance on where to begin? (equation, link, anything)



"If there was a total energy change of 3.32x10^5J during the burning of your pie, what amount of heat was released?



I think I will be able to answer this one after I get help with the previous question.



What was the enthalpy change in the reaction given your results? (remember the sign conventions when determining your answer)



With this one, I assume I need to find the balanced equation first, correct?





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