Enthalpy question

HungLikeJesus · 10-31-2011, 08:07 PM

It's been a while since I thought about this, and I'm too lazy to go find my thermodynamics text book, so could someone remind me why water/steam at

1) 180 psia and 373.1°F, and
2) 32.75 psia and 317.5°F

both have an enthalpy of 1197.3 Btu/lbm*°R?

infinite monkey · 10-31-2011, 08:23 PM

No.

Lamplighter · 10-31-2011, 08:33 PM

triple point or critical point ?

One of your values is the same as critical point vs critical pressure for water.

Oooops, I hit the submit button too soon.
I needed to add: "I really don't have a clue"

HungLikeJesus · 10-31-2011, 08:48 PM

Thanks LL - here's the answer.

Lamplighter · 10-31-2011, 09:51 PM

I'm glad you found your answer.

Like I said, I really didn't have a clue.
It's been more than 50 yrs since I took PhysChem

infinite monkey · 11-01-2011, 07:45 AM

Quote:

Originally Posted by HungLikeJesus

Thanks LL - here's the answer.

I still say no. Mostly because that link heads nowhere.

I'm not having empathy for ur enthalpy.

Lamplighter · 11-01-2011, 09:10 AM

IM, I have the same problem.
I have more empathy for entropy than for enthalpy.

I used to work on the 3rd floor and the ice machine was in the basement.
I would tell people I was going to get some negative entropy.

infinite monkey · 11-01-2011, 09:17 AM

Let's recap: you have more empathy for entropy than you do for enthalpy, in fact, one might say that when it comes to enthalpy you feel apathy. Sorry if I'm being pithy.

Lamplighter · 11-01-2011, 09:21 AM

Not at all pithy. Maybe our enthalpy is just reaching supercritical.

limey · 11-01-2011, 02:27 PM

Isn't it time to call in phlthy here?

BigV · 11-01-2011, 02:38 PM

I once posed this riddle to my friends:

What is the opposite of entropy?

Happy Monkey · 11-01-2011, 03:07 PM

hdoL+ua

Lamplighter · 11-01-2011, 03:25 PM

Quote:

Originally Posted by BigV

I once posed this riddle to my friends:

What is the opposite of entropy?

The Cellar

HungLikeJesus · 11-01-2011, 03:47 PM

Quote:

Originally Posted by BigV

I once posed this riddle to my friends:

What is the opposite of entropy?

Extropy, obviously.

Clodfobble · 11-02-2011, 08:41 AM

Quote:

Originally Posted by BigV

What is the opposite of entropy?

Ice.

10-31-2011, 08:07 PM	#1
HungLikeJesus Only looks like a disaster tourist Join Date: Feb 2007 Location: above 7,000 feet Posts: 7,208	Enthalpy question It's been a while since I thought about this, and I'm too lazy to go find my thermodynamics text book, so could someone remind me why water/steam at 1) 180 psia and 373.1°F, and 2) 32.75 psia and 317.5°F both have an enthalpy of 1197.3 Btu/lbm*°R? __________________ Keep Your Bodies Off My Lawn SteveDallas's Random Thread Picker.

10-31-2011, 08:48 PM	#4
HungLikeJesus Only looks like a disaster tourist Join Date: Feb 2007 Location: above 7,000 feet Posts: 7,208	Thanks LL - here's the answer. __________________ Keep Your Bodies Off My Lawn SteveDallas's Random Thread Picker.

11-01-2011, 02:27 PM	#10
limey Encroaching on your decrees Join Date: Feb 2004 Location: An island within the south-west coast of Scotland Posts: 7,016	Isn't it time to call in phlthy here? __________________ Living it up on the edge ... of civilisation, within the southwest coast of

11-01-2011, 02:38 PM	#11
BigV Goon Squad Leader Join Date: Nov 2004 Location: Seattle Posts: 27,063	I once posed this riddle to my friends: What is the opposite of entropy? __________________ Be Just and Fear Not.

11-01-2011, 03:07 PM	#12
Happy Monkey I think this line's mostly filler. Join Date: Jan 2003 Location: DC Posts: 13,575	hdoL+ua __________________ _________________ \|...............\| We live in the nick of times. \| Len 17, Wid 3 \| \|_______________\| [pics]

10-31-2011, 08:23 PM	#2
infinite monkey Person who doesn't update the user title Join Date: Mar 2011 Posts: 13,002	No.

10-31-2011, 08:33 PM	#3
Lamplighter Person who doesn't update the user title Join Date: Jun 2010 Location: Bottom lands of the Missoula floods Posts: 6,402	triple point or critical point ? One of your values is the same as critical point vs critical pressure for water. Oooops, I hit the submit button too soon. I needed to add: "I really don't have a clue"

10-31-2011, 09:51 PM	#5
Lamplighter Person who doesn't update the user title Join Date: Jun 2010 Location: Bottom lands of the Missoula floods Posts: 6,402	I'm glad you found your answer. Like I said, I really didn't have a clue. It's been more than 50 yrs since I took PhysChem

11-01-2011, 09:10 AM	#7
Lamplighter Person who doesn't update the user title Join Date: Jun 2010 Location: Bottom lands of the Missoula floods Posts: 6,402	IM, I have the same problem. I have more empathy for entropy than for enthalpy. I used to work on the 3rd floor and the ice machine was in the basement. I would tell people I was going to get some negative entropy.

11-01-2011, 09:17 AM	#8
infinite monkey Person who doesn't update the user title Join Date: Mar 2011 Posts: 13,002	Let's recap: you have more empathy for entropy than you do for enthalpy, in fact, one might say that when it comes to enthalpy you feel apathy. Sorry if I'm being pithy.

11-01-2011, 09:21 AM	#9
Lamplighter Person who doesn't update the user title Join Date: Jun 2010 Location: Bottom lands of the Missoula floods Posts: 6,402	Not at all pithy. Maybe our enthalpy is just reaching supercritical.

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