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Another homework thread. Thermodynamics help

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WorthDaMoney
Posts: 1140 - Karma: 741
so we're doing p-v (pressure vs specific volume) and T-v (temperature vs specific volume) graphs and im understanding it fine. but theres a question on my assignment that asks to draw the p-v and T-v graph of water when its p = 1 bar, and T = -12 celcius. from the temperature and pressure tables in the back of my book, it only shows temperatures over 0 celcius.

so my question is:
how do you draw a p-v graph for water at p = 1 bar and T = -12 celcius ?

+K for legit attempts to help
Sep 29 2011 4:49PM
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AWALLRUS.
Posts: 5762 - Karma: 223
YOU GOTTA POKE HOLES IN THAT SHIT AND LET THE HOT AIR OUT.
Sep 29 2011 4:54PM
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come_at_me_bro
Posts: 494 - Karma: 19

Sep 29 2011 4:57PM
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H8CH
Posts: 2709 - Karma: 218
At 1 atmosphere, water will be frozen (solid) at 0 degree C......

that's probably why your chart only goes to o deg c.

Sep 29 2011 4:58PM
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moarplease
Posts: 293 - Karma: 15
not sure about your book but sometimes the temperatures are given in kelvin. if thats the case for you, change to kelvin and interpolate that shit.
Sep 29 2011 4:58PM
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WorthDaMoney
Posts: 1140 - Karma: 741
its kind of obvious when someones a post whore . wasnt even close to a funny comment, and it didnt answer my question.

fuck off
Sep 29 2011 4:58PM
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WorthDaMoney
Posts: 1140 - Karma: 741
no its given in celcius which is what i dont get because from what ive heard, they normally go to absolute zero.

and as for the other comment about it being solid, ive only learnt about p-v and T-v graphs for liquid, saturated vapour and superheated vapour. ill google a temperature table for solid ice

+K
Sep 29 2011 5:00PM
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daskis
Posts: 1828 - Karma: 356
I think as on a regular x and y axis graph, you would simply start the curve at p=1, V=0 instead of starting at (0,0). I've taken 3 chemistry classes and am currently taking Organic Chemistry, and I've never had to do this haha.
Sep 29 2011 5:01PM
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daskis
Posts: 1828 - Karma: 356
Dub post, but I just realized how dumb I am for saying what I just did because next semester I have a course entitled "Thermodynamics"
Sep 29 2011 5:04PM
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H8CH
Posts: 2709 - Karma: 218
The only way you can use water in liquid state is to change the pressure at -12 degree c. Unless the water is seawater, aka brine. But sounds like a trick question - but don't quote me as i haven't seen any of your class work etc.

0 degree C = circa 273 k.

Have you learnt about PVT calculations etc? We do a lot of that in reservoir engineering and flow assurance.
Sep 29 2011 5:07PM
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AWALLRUS.
Posts: 5762 - Karma: 223
YOU'RE THE FOOL MAKING A THREAD ON A SKIING WEBSITE ABOUT YOUR HOMEWORK, EVEN THOUGH YOU KNOW THERES ALREADY ABOUT 200 FROM THIS MONTH ALONE.

NOBODY IN NSG GIVES A SHIT ABOUT YOUR HOMEWORK, ASK YOUR MOM OR SOMETHING.
Sep 29 2011 5:09PM
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General_Ripper
Posts: 3327 - Karma: 189
Arn't they gona be like a strait lines or somethingy
Sep 29 2011 5:10PM
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WorthDaMoney
Posts: 1140 - Karma: 741
on the p-v T-v graphs we're making its to show that we have a general understand of how to plot both graphs with only the substance, and temperature and pressure values. the only specific values we plot are the values where the isobaric (sp) and bell curve intersect and at what point our substance is at on the graph.

you'll learn it next term, its fun !...
Sep 29 2011 5:10PM
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WorthDaMoney
Posts: 1140 - Karma: 741
unlike you im actually learning something other than highschool art. so fuck off. get out of my thread. i clearly said in the title that it was a homework thread. if you dont want to read it, then dont. i dont want to have to respond to you again.

yes i mad.

i dont fucking like you awallace
Sep 29 2011 5:14PM
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AdamP
Posts: 13 - Karma: 10
Dear STEAMY-J.613's,
I would be very surprised if you'd see temperature in Celsius in any equation or graph in chemistry. It sounds like youre dealing with the ideal gas law (PV=nRT). Have you tried to analyze your data after converting the temperature to Kelvin? You prolly know this but to convert it, just add 273.15 to the temperature in Celsius.
Sep 29 2011 5:17PM
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AWALLRUS.
Posts: 5762 - Karma: 223
HAHAHA HIGHSCHOOL ART.


Sep 29 2011 5:17PM
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WorthDaMoney
Posts: 1140 - Karma: 741
ya i know about changing the pressure to get different phase changing temperatures. if by PVT you mean pv = RT, then yes we have briefly and ive done it in highschool before too.if youre talking about the pvT graph, we have looked at those to see where the pv and Tv graphs come from, but only for that reason. i know there are sections for solid states on the pv and Tv graphs, i just dont know how to graph with a solid substance
Sep 29 2011 5:20PM
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WorthDaMoney
Posts: 1140 - Karma: 741
well, surprise ! i did check before making this thread that it was infact celcius that the tables were dealing with
Sep 29 2011 5:22PM
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H8CH
Posts: 2709 - Karma: 218
How old are you and what level is this?

I'm an old engineer and have forgotten so much of this shit...school was a long time ago. ha.


Sep 29 2011 5:29PM
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daskis
Posts: 1828 - Karma: 356
http://www.eng.fsu.edu/~dommelen/courses/eml3100/aids/tables/index.html
Sep 29 2011 5:30PM
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WorthDaMoney
Posts: 1140 - Karma: 741
im in second year mechanical . this is the second year thermo course. its really not that hard, but he hasnt gone over how to draw a solid substance on the pv Tv graphs. im pretty sure i can do it on the Tv graph because my pressure of 1 bar in on the table. so i draw my isobaric line at 99.63 celcius (from the table) and then plot my point on the compressed liquid side of the bell curve (now in the solid state i guess). the Tv plot is not a problem because it is at a constant pressure of 1 bar, but the pv graph must be at a constant temperature of -12, and there is no -12 celcius on my tables so i cant figure out where the isobaric line rests on the pv graph

hopefully that time it made sense
Sep 29 2011 5:45PM
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WorthDaMoney
Posts: 1140 - Karma: 741
ya those are the types of graphs im trying to draw but it doesnt say anything about any temperatures under 0 celcius
Sep 29 2011 5:47PM
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