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
Heat capacity: Heat capacity of furnace depend on (1)         Thermal conductivity (2) Specific heat and (3) Specific gravity of refractory. The dense and heavy fire clay

How to design a reaction vessel for esterification reaction

1.      In the system shown schematically below, water is supplied to a spray nozzle by a gear pump with a constant output of 20 US gpm. The flow rate of water discharged through t

Why protons doesn''t react which each other?

Advantages of cold working (i)  No heat is needed. (ii)  Better surface finish is get. (iii)  Superior dimension control. (iv)  Improved strength and hardness properti

ACTIVITY 1 to classify hazardous chemicals based on the information given on the labels Requirements Bottles containing chemicals (generally used in a lab) = 20 in number.

how tofind renold constant..

Ask queswhat is axontion #Minimum 100 words accepted#

Why do we need to produce of Dimethyl ether? Today''s and future demands and supplies...Who are the consumers? (Consumer from industry and consumer''s habit).Safety precautions of

Prior preparation for fixing and staining animal tissue and/or plant tissues: Find out what procedure the lab technician follows for preparing fixative (either plant andor animal)