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CHEM TWO H. MID TERM QUESTION!!!!

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captainEMERICA
Posts: 1386 - Karma: 122
hello,
My chem midterm is tomorrow and I have a question that I need some help with and hope one of you lovely people is a chem wiz. Anyway I can do questions like how much energy does it take for 10g of H2O at 30C to reach 120C but cant do questions like this ex. what is the final temp. when 10g or H2O at -20C are added to 25g of H2O at 65C. If anybody knows how to do this I would give mad K and a lot of good vibes

Thanks!
Jan 23 2011 9:14PM
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captainEMERICA
Posts: 1386 - Karma: 122
the formula is Q=MC(delta)T but because of energy of fusion and energy of vaporization you have to take everything one state of matter at a time. I just dont know how the variables are set up once I get that I can (probs) figure it out.
Jan 23 2011 9:19PM
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a_pla5tic_bag
Posts: 9210 - Karma: 5,357
yeah. i did an experiment with this last semester and I don't quite remember what all the math was. there's definitely formulas and specific heats you need to know.
Jan 23 2011 9:21PM
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Rumi.
Posts: 1231 - Karma: 556
give me 10 mins and i'll show you how...
Jan 23 2011 9:21PM
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captainEMERICA
Posts: 1386 - Karma: 122
that would be magic THANK YOU
Jan 23 2011 9:22PM
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Arabian.
Posts: 9632 - Karma: 54
when 10g or H2O at -20C are added to 25g of H2O at 65C.


85 degree change in temp. 25g is 71.4% of the total mass = 40.69C.
Jan 23 2011 9:22PM
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captainEMERICA
Posts: 1386 - Karma: 122
you are not taking into account heat of fusion or heat of vaporization (I think)
Jan 23 2011 9:27PM
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Rumi.
Posts: 1231 - Karma: 556

damn you beat me to it

Jan 23 2011 9:27PM
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Arabian.
Posts: 9632 - Karma: 54
I'm not doing the fucking kCal count for you. Do it yourself. I started you off by giving you a start.
Jan 23 2011 9:33PM
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Arabian.
Posts: 9632 - Karma: 54
this sounds retarded. I gave you the start. now finish it.
Jan 23 2011 9:33PM
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captainEMERICA
Posts: 1386 - Karma: 122
The only reason I ask is because this is not how we learned in class, I will give it a shot thanks
Jan 23 2011 9:37PM
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No_Dub
Posts: 3357 - Karma: 294
fuck chem
Jan 23 2011 9:38PM
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Dylan_
Posts: 9824 - Karma: 1,403
assuming youre in hs. Don't you have a reference table... ?
Jan 23 2011 9:40PM
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captainEMERICA
Posts: 1386 - Karma: 122
Naw my chem teacher is like an ex hippie and does not believe in like, conventional teaching methods with a text book and everything, and yea i am in my senior year, after this test I can basically not care anymore, pretty stoked
Jan 23 2011 10:45PM
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a_pla5tic_bag
Posts: 9210 - Karma: 5,357
haha, well you need to know those specific heat values. look them up. i did this using a calorimeter at school.
Jan 23 2011 10:49PM
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