I have no idea how to do this problem, please help me! Fill in missing informati

Question

I have no idea how to do this problem, please help me!

Fill in missing information in the tables below approximating transitions a ? b, c ? d as isothermal at corresponding bath temperatures (they are actually adiabatic transitions but such approximation works well in our case), and transitions b ? c, d ? a as isobaric.

What is useful mechanical work done in lifting the mass?

Wuseful=_____ mJ

In the lab you will not be able to measure the values of the pressure and the volume during the transitions, but rather the end points a,b,c, and d alone. Your p?V diagram will look more like the bottom panel in the figure above where we approximate the transitions between the states with straight lines. To calculate the area we can use the following approximation: Wi ?f = ?if pdV ? [(pi+pf)/2]*(Vf-Vi)

Calculate the thermodynamic work for each transition:

What is the total thermodynamic work done by the system?

Wthermodynamic= _____ mJ

State Variable State a State b State c State d kPa 101.5 104.2 101.5 V [ml] 17.82 17.36 T [°C] 1.88 1.88 68.38 68.38

Explanation / Answer

Apply PaVa= Pb Vb ;

101.5*17.82 = Pb*17.36 ;

Pb=104.19 kPa

Vb/Tb = Vc/Tc

17.36/(273+1.88) = Vc/(68.38+273) ;

Vc= 21.56 ml

PcVc=PdVd

104.2*21.56=101.5*Vd; Vd=22.13 ml

Useful work done(W)= P*change in volume; change in volume=22.13-17.82 ;

pressure= force/ A ; to lift the mass the required force= mg= 48.1*10-3 *9.8; and A=1.77*10-4

So, W= 0.011 J =11.48 mJ

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