Processes for ideal gas and second law of thermodynamics (5th Day).

Spring 2015
Professor Mason
March, 10th

Processes for Ideal Gas
In March 10th's class, first thing we learned in the morning was about the processes or conditions of an ideal gas, and those are Isothermal, Adiabatic, Isobaric, and Isochoric (Isovolumetric).  The simple things to remember all of those are: Isothermal has a Temperature (T) that is constant or don't change, such as cup of coffee, the temperature is constant and molecules move faster [Q = mLT]; Adiabtic has a heat (Q) that is constant or don't change; Isobaric has a Pressure (P) that is constant or don't change, such as [delta U = Q - W] or [W = P*delta V]; Isochoric or Isovolumetric has a volume (V) that is constant or don't change, so that the heat would be able to change.

Heated Rubber Band
In class, we did an experiment on rubber band, which what we did was heating the rubber band and predicted how it would happen. We predicted that the rubber band would expand, however, our prediction was not right, and it was supposed to be shrinking when heated instead because it is made of polymer.

The next thing after heating the rubber band was conveyor. By the method of heating the rubber band, we can also apply this method in conveyor because it can do the same work as heating rubber band does. There is a 4 step cycle that creates a cycle to bring the object from one conveyor to the next conveyor. That can work because the rubber band inside the conveyor is heated so it can make a cycle.

Efficiency
In class, we learned about efficiency, which has the definition of [(how much you want)/(how much you have to put in)]; for example, we put in heat, and get out the work done: [delta E = Q - W] = [Qh-Qc-W] or [W=Qh-Qc]. For instance, a block full of Qh turns into a block divided by 1/4 of work and 3/4 of Qc. The definition of efficiency is [e = W/Qh].

Theoretical Analysis of a Heat Engine Cycle

This heat engine cycle that we learned in class has the same method as the syringe with a heated empty beaker attached to the syringe. Back when we learned the experiment about the syringe, we knew that when the beaker has a room temperature surrounding it, the plunger of the syringe slides down slowly, vice-versa.

We did an experiment that involves the syringe as well. However, this time is about heat engine, and professor Mason showed us the graph of the experiment based on the pictures on the sides.

There are 4 points mentioned in the lab book, and we need to do a calculations and a diagram, as well as a E internal table based on the data. We also put an object, which was happened to be an eraser and a marker on top of the plunger. Then we need to increase all the volume data by 2 cc because we started off from 2 cc. We used point #3 because it is the closest one to the atmosphere in order to find [PV = nRT] and [Q = mc*delta T].

We found the Energy internal based on the data in the pictures. Before we calculated the E int, we need to find the Q and the W first by using [W = P (V2-V1)]. Then we can calculate E int using [3/2 (P*V)]. The data in the book shows that point #1 and point #2 has the same P, which is P = 1.02x10^5. Point #3 and point #4 has the same P, whic his P = 0.79x10^5. Point #1 and point #4 has the same V, which is V = 0.08. Point #2 and point #3 has the same V, which is V = 0.1. The work done = the area enclosed.

After we calculated all the data, we need to calculate the net work done, which we found to be 460J; [W tot = W1 + W2 + W3 +W4].