Constant temperature change in a system

• May 14, 2003

• #2

quark

Mechanical

Jan 23, 2002

3,409

IN

Yes. Your notion was wrong. For example consider melting of Ice or boiling of water.

In both cases, you should supply latent heat to change the phases but temperature remains constant.

 

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• May 14, 2003

• Thread starter
• #3

Ozone

Chemical

Apr 10, 2003

5

NL

I am aware of latent heat, i forget to state that the heat added was not latent. Visible heat tranfer to a gas that is what i am talking about here.

 

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• May 14, 2003

• #4

25362

Chemical

Jan 5, 2003

4,826

CA

An ideal gas (pV = nRT) can be expanded reversibly and isothermally by the absorption of heat. Since the internal energy of an ideal gas cannot change in an isothermal process, dU= 0 = dQ + dW. For a mechanical reversible non-flow process Q = -W = RTln(V₂/V₁), since P₁/P₂ = V₂/V₁, one can also write Q = -W = RT ln(P₁/P₂).

 

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• May 14, 2003

• #5

hacksaw

Mechanical

Dec 7, 2002

2,587

US

visible heat that is a new one. unless you are alluding to real gas supercritical behavior, 25362 comments are right on.

 

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• May 15, 2003

• Thread starter
• #6

Ozone

Chemical

Apr 10, 2003

5

NL

thanks to all who contributed to clarify me. Especially 25362 and to HACKSAW , i actually meant sensible heat thanks for the observation. hoping we could share knowledge the more in this forum.

 

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• May 15, 2003

• #7

hacksaw

Mechanical

Dec 7, 2002

2,587

US

any ideas on how estimate the specific of molten iron at 1000 m hydrostatic head?

 

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• May 15, 2003

• #8

phex

Chemical

Mar 4, 2003

234

DE

i'd like to help, but what 'specific' are u looking for?

 

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• May 15, 2003

• #9

quark

Mechanical

Jan 23, 2002

3,409

IN

First of all I am very sorry to trivialize the original post and I agree that I should have a little bit high estimation.

25362 is correct asusual. But that is possible (and is evident from his equation) if and only if work is done by the system external to it.

Once again I am sorry.

 

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• May 19, 2003

• Thread starter
• #10

Ozone

Chemical

Apr 10, 2003

5

NL

to hacksaw, ur question is not clear. specific what of iron?
to quark: u are really a nice guy. u need not apologise, i completely understand.

 

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• May 19, 2003

• #11

hacksaw

Mechanical

Dec 7, 2002

2,587

US

the constant pressure and constant volume specific heat

 

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• May 19, 2003

• #12

phex

Chemical

Mar 4, 2003

234

DE

to hacksaw:

perhaps this is of some worth for you.

http://www.moderncasting.com/archive/WebOnly/0802/02_146.pdf

 

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