A 20.00 mol sample of gaseous ethanol is held at 5.50 x 10² K in a cylinder with a piston set such that the volume is 12.00 L. The ethanol expands isothermally and reversibly to a final volume of 45.00 L. Consider ethanol as an ideal gas. Plot the relevant indicator diagram (Make life easier, use a spreadsheet! Be sure to follow the guidance provided in Bonus Lesson 2, part A!). Then, determine the value of the quantities q, w, and AU (signs are important!) for this expansion.
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
I got -46.7 KJ for part a but +100 KJ for part b (the van der waals version), I probably missed a negative sign somewhere, this question is for both a and b
![Now consider the same expansion treating ethanol as a van der Waals gas. (Look up the
van der Waals parameters in E&R appendix Table 7.4). Generate an indicator diagram
(ideally, combine this indicator diagram with the one above, so that both curves will be
in the same graph.) Next, you will need to derive an expression for the work associated
with isothermal expansions (or compressions) on a van der Waals gas. This equation
will be analogous to w = nRT In for an ideal gas. (Yes, you will need to work out an
Vi
integral; see the Bonus Lesson 2 part B document for guidance, if necessary.) Calculate
q, w, and AU for the expansion.
[HINT: for determining AU, you should start with the total differential expression and think about how
you can determine the values of the various partial derivatives. In some cases, you have already worked
with these values for other examples, so you just need to incorporate the relevant specific quantities for
this case.]](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F31b824f0-965a-48c2-af33-3e7e6a35a649%2F27a2d65e-6088-4f11-b0ec-e48871fafbc1%2Fwr1kgj_processed.png&w=3840&q=75)
A 20.00 mol sample of ethanol at is expanded isothermally and reversibly from to . We are required to find out the value of q, w and by considering the gaseous ethanol as an ideal gas and as a Van der Waal gas.
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