Find the internal energy and entropy , Chemical Engineering

1 ΔS on rapid decompression

Steam at 400C, 100 bar in an insulated cylinder is suddenly decompressed to 10 bar, by unlocking the piston and allowing the gas to expand, with a constant external pressure of 10 bar applied to the piston. Find the final temperature T2, and the entropy change ΔS.

To answer the problem, ask yourself the following questions:

1) How much work is done as the steam expands?

2) What does energy conservation tell you in this situation?

2 Reversible heating with reservoirs

a)  A system with constant heat capacity CP and initial temperature T1 is heated by contacting a reservoir at Tf . Find the entropy change of the system, reservoir, and system plus reservoir. Evaluate the total entropy change assuming Tf = 2T1.

b) The same system is now heated in two stages, by first contacting with a reservoir at T2 halfway between T1 and Tf , then by contacting with the reservoir at Tf . Again find the entropy change of system, reservoirs, and system plus reservoirs, and again evaluate the total entropy change.

c)  The system is now heated in n stages, by contacting with reservoirs at n equally spaced

Ti between T1 and Tf . Write an expression for the entropy change of the system, reservoirs, and system plus reservoirs. How does this compare to the limit of reversible heating as n becomes large?

3 Carnot cycle in steam

Consider a Carnot heat engine operating with steam as the working uid, between reservoirs at

TL = 200C and TH = 500C.

Do the following, using the steam tables:

1) Sketch the cycle on a PV diagram. Label the state points 1, 2, 3, 4 starting with the low-pressure, low-temperature state.

2)  Let the lowest pressure in the cycle (P1) be 1 bar, and the highest (P3) be 80 bar. Find the values of P2 and P4.

3)  Compute the heat Q and work W on each leg of the cycle; tabulate your results (SI units).

4)  Compute the efficiency of this cycle as a heat engine. Compare to the ideal-gas result for the Carnot efficiency, and briey comment on the comparison.

4 van der Waals U, S

For a substance described by the van der Waals equation of state with a constant heat capacity CV :

1) Find the internal energy U(T; V ), relative to a reference state at some T0; V0.

2) Find the entropy S(T; V ), likewise.

Posted Date: 2/20/2013 5:20:18 AM | Location : United States

Related Discussions:- Find the internal energy and entropy , Assignment Help, Ask Question on Find the internal energy and entropy , Get Answer, Expert's Help, Find the internal energy and entropy Discussions

Write discussion on Find the internal energy and entropy
Your posts are moderated
Related Questions
The objective of the research is to empirically develop correlations between convection heat transfer and these above mentioned non-dimensional in numbers. The simple empirical cor

1. Select a process variable (pressure / temperature / level / flow) and conduct a literature survey to determine recent developments in process instrumentation field. Ide

merits and demerits of free radical polymerisation

Explain with suitable diagrams the atomic model of diffusion. Atomic Model of Diffusion Diffusion happens as a result of repeated jumps of atoms from their sites to other ne

A contaminated soil contains 100 mg metals/kg soil (all metals are readily condensable), 50,000 mg S/kg soil, 1,000 mg F/kg soil, 980 mg/Kg of VOCs and 40,000 mg Cl/kg soil and is

Check in and checkout procedure a. Location of Key: Enquire from the technicians as to who opens the laboratory. Does the lab staff have to take the keys from the office or

Point defects: Point defects are defects which are not extended in space in any dimension. There is no strict limit for how small a "point" defect should be, but typically the ter

Soft magnetic materials  Soft magnetic materials are majorly utilized in those applications in which the soft material has to amplify the flux occured by the electrical current