/sci/ - Science & Math

[Anonymous No.1953747]

Hey, /sci/, this is /a/ coming in need of dire assistance. I just transfered to a new curriculum facility, and the Oceanography class I'm taking is very Chemistry oriented because it's a prerequisite here, but I didn't take the class.

Could a friendly anon please help me with a few problems?

[EK No.1953763]

maybe.. i'll have a shot. post the problem.

[Anonymous No.1953802]

>>1953763

Sorry. I had to jetson off. Here's one:

How much energy must be absorbed by 20g of water to increase its temperature from 283*C to 303*C?

I took Anatomy, so I'm on the far end of the spectrum from this.

[EK No.1953835]

Q = mL
(energy = mass X latent heat capacity of water)
Q = 0.02 X ...erm
...well at 283 degrees C the water will already have all boiled and evaporated...so im not sure if this would even work... and maybe your supposed to use the latent heat vaporization.
erm, i think im outta my league here, but here as wiki that might help.
http://en.wikipedia.org/wiki/Latent_heat

[Anonymous No.1953853]

q = mcT
q = energy needed
m = 0.02 kg
T = 303-283
c = 4.18 for liquid, 1.865 for gas

[EK No.1953861]

C=specific heat of water=4.1855 joule/gram
... i think
so, Q=4.1855X20X20

=1674.2 joules

[Anonymous No.1953872]

>>1953861
no, you're using the specific heat (heat capacity) for liquid water. You need to use the heat capacity for steam, which is in the table at the bottom of this page:
http://en.wikipedia.org/wiki/Heat_capacity

[EK No.1953878]

>>1953872
ah yeh, sorry my bad.
Q = 2.080 X 20 X 20 = 832J

lol, i actually already had that wiki page open as well...*facepalm*

[Anonymous No.1953902]

The question states water. I guess that OP has made a mistake. The temperatures should be 28.3 and 30.3 then the question would be sensible. Why did nobody spot the obvious flaw that someone studying Oceanography would be dealing with temperatures of water at 300 degrees.
>How much energy must be absorbed by 20g of water to increase its temperature from 28.3*C to 30.3*C?
Fixed

[EK No.1953906]

>>1953902
don't change his numbers! i'm sure he knows what he means. and he didn't even make a mistake, steam is still water, just in its gaseous state, and ice is water, but in a solid state, its still accurate to call both water.

[alialc !aLIaLc1Vso No.1953907]

i always thought it was

delta H = -mC delta T...

[Anonymous No.1953910]

>Why did nobody spot the obvious flaw that someone studying Oceanography would be dealing with temperatures of water at 300 degrees.

[EK No.1953911]

>Why did nobody spot the obvious flaw that someone studying Oceanography would be dealing with temperatures of water at 300 degrees.

also, black smokers (they underwater geysers i mean...you probable racist... lol jk, ;) ..yeh)
are underwater and can be as hot as 400 degrees C. so there is no reason an oceanographer won't be dealing with temperatures this high.

[Anonymous No.1953914]

>>1953906
You need to apply a little common sense. OP has made a mistake or is trolling. Oceanography does not deal with water at 300 degrees Celsius.
There is a possibility that they mean Kelvin instead of Celsius.

[EK No.1953917]

>>1953910

...god damn it!
fucking inb4's well played anon...well played.

[Anonymous No.1953933]

>>1953911
In which case it would be water not steam?

[Anonymous No.1953938]

>>1953914
That's true -- it could be a mistake for kelvin, as that is around room temp.

[EK No.1953941]

>>1953933
erm...hmm... if its over 100 degrees C it should technically be steam, for a few seconds...but it gets cooled rapidly by the surrounding cold water, so it will reverting to liquid state very quickly.

... i say, if dealing with temperatures over 100 degrees C, so 283-->303 you should use heat capacity for steam, so 2.080 joules/gram.

[Rebirth !NuJBxbKoek No.1953950]

>>1953941

God damnit, go to bed. You're the most resilient and informative namefag I know, but you have got to get some rest sometime. I'm saging this thread so you get the fuck off of this board and get some sleep.

Seriously, you're a smart guy, but you spend too much fucking time here. Go elsewhere.

[EK No.1953954]

>>1953950
>you're a smart guy
*girl...and thank you :)
>you spend too much fucking time here. Go elsewhere
yeh probably true... fine i'll go for now. but i'll be back later ;)

[Anonymous No.1955005]

>>1953954

Wait, is EK actually Kriss?

:o