## Thermodynamics Lab - Heat Engines

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Evaluation of Data - Part 1

y=mx+b

b=Volume of Gas in Flask and Tubing

b = 165.8 mL of gas

Graph - Part 2

Evaluation of Data - Part 2

1.

 Step Process Q W 1 Isochoric Heating + 0 + 2 Isothermal Expansion + - 0 3 Isochoric Cooling - 0 - 4 Isothermal Compression - + 0

2. Area under PV curve represents the work done by the system. The sign is different because the integral under the PV curve under isothermal expansion is to the right (thus a positive integral) whereas the isothermal expansion integrates to the left (and thus produces a negative integral). One must be cautious though in realizing this is work done by the system, not on the system, so from a system-centric perception, we must flip the signs accordingly.

3.  T remains constant in isothermal processes.

4. 0.2843 L-kPa = 0.2843 J work done by the system.

Evaluation of Data - Three Process Cycle

 Step Process Q W 1 Isochoric Heating + 0 + 2 Isothermal Expansion + - 0 3 Isobaric Compression - + -

2. Either lubricate the piston so effectively that it removes (almost) all the friction inherent to the plunger's movement so it will move on its own during the process or manually compress the piston while it is moving, but this option presents inherent human error.

Extension Questions

1. It would be far less than that of the 1st system, in fact the net work by the system on the surroundings would be - not +. From a system-centric perspective, the work on the system by the surroundings is + not -.

2. The Carnot engine replaces the isochoric heating and cooling processes with adiabatic expansion and compression processes. In this sense, the reaction is made reversible, unlike the phase in step 1.

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