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
a. Explain the problems of flooding and channeling in packed tower

Hard magnetic materials   Permanent magnets are used as passive generators of magnetic field. To produce and maintain the magnetic field, a material should have both high resid

PREPARATION OF COMPARATIVE CHART You are given three envelopes containing quotations from three firms for two items. You will prepare a comparative chart in the format given be

complete process of reverberetoy furnace?

It is desired to concentrate a NaOH solution from 12.5 % to 40% in a double effect evaporator. 50,000 lb/hr of feed solution enters the evaporator at 120 o F, and steam at 15 psig

PROCEDURE : Visit any lab (physics, chemistry or biology) of your study centre or any other you can get access to and note its features. To guide you through we have listed below

Explain Loss Angle Loss Angle can be described as the arc-tangent of the electrical dissipation factor.

a) The vacuum in the headspace of a can of food is normally formed by "hot fill" exhausting - that is, the cans are closed when the can is filled with product at a temperature of 8

air flows through apipe at arte of 200L/S. The pipe of two sections of diameters 20cm and 10cm with asmoth reducing section the pressure are difference between the two pipe sectio

Can I have online tuition sessions for reaction engineering ?