Question

A system consists of 2.320 g of carbon monoxide gas initially at temperature 400.0 K and pressure 0.6250 bar. Assume the heat capacity of carbon monoxide is constant at the value found for 298.15 K in the data tables of the Appendix (see also Figure 2.8). The system undergoes the following cyclic process: Step a) Reversible isothermal expansion to double the initial volume. Step b) Constant volume extraction of heat from the system (to a temperature and pressure consistent with step c) Step c) Reversible adiabatic compression to the initial conditions. Make a quantitative plot of this cycle on a P - V graph. For each step and the cycle overall, calculate: q, w, Delta U, and delta H. Show your work and make a table of the results.

Answer 1

Answer:
PV = nRT

V = nRT/P

where n = given weight of molecule/ gram molecular weight of molecule

= 2.320/28

= 0.083

V₁= (0.083)(0.0821)(400)/(0.6251)

=4.35 L

Volume at Temperature = 298.1

V₂ = (0.083)(0.0821)(291.1)/(0.6251)

= 3.25 L

Change in Volume = V₁- V₂

∆V= 4.35-3.25

= 1.1 L or 1100 mL

Thus work done is,

W = -P∆V

= -(0.6251)(1100)

=-687.1 J

Thus 687.1 KJ work hasbeen done during compression of gas from higher temperature to lower temperature.

q=mC∆T

C = 1.048 and this remains constant during compression

m = 28

q = (28)*(1.048)*(400-298.15)

= 2988.68

∆U = q + W

= (2988.68) - (687.1)

= 2301.58