Thread: Chemistry... I freakin hate it

Originally Posted by H?b

biology > chemistry

physics>biology>chemistry


....


computerscience >physics >bio>chem


...
compsci + physics.... pricesless awsome...'ness

bbl, now I have lab :3

Originally Posted by H?b

ha, I have NEVER in my schooling... have taken a Physics class. Fuck physics.

NOW thats below the belt...

Originally Posted by Bunni

Originally Posted by H?b

biology > chemistry

physics>biology>chemistry


....


computerscience >physics >bio>chem


...
compsci + physics.... pricesless awsome...'ness

Ok, so let me get this straight....

If chem is < bio...and kraker sucks at chem, but is good at bio..that would mean that kraker=bio>chem...

But by that...you could say...god>compsci+phiscs=pricesless awesome+bio=kraker

Then....since i banged a compsci major once...and bunni gave me a reach around...you could say

Compsci+reacharound+B(compsci-major)priceless awesome=God


Kraker=God!

damn sacred beat me to it. but water chemistry is more up my alley right now, seeing as how im an environmental/water resources engineer.

Thanks for the help draco and sacredsarcasm, I see I was supposed to be solving for V now, DUH.

Originally Posted by Imisnew2

And now for PART 2!!!!!

If the diver suddenly surfaces, ___ mL of N2 gas, in the form of tiny bubbles, are released into the bloodstream from each liter of blood (at 37.0 ºC and 1 atm).

I've kinda got the idea so I'll just do my work here.

P = MRT - PV = nRT, solving for n - n = PV/RT.

P=1atm
V=1L
R=0.0821 (constant)
T=37+273=310K

(1*1)/(310*0.0821)
=
0.03929 mol N2

when dissolved in water(blood) 1g is VERY close to 1mL so... I'm thinking this
we get the grams of N2 Might be wrong...

0.03929 * 28.01~
=
1.10054g N2
=
1.10054mL N2

BUT- Lo' and behold I did something wrong Can anyone help me out?

wait a sec....

0.0012531 mol/L (4x pressure - 1x pressure)

0.0012531 * 28.01
=
0.035099331 g/L
=
0.035099331 mL/L

BAH! Still didnt work...

So fixing,
V = nRT/P

n = x4atm - x1atm = 0.0012531 mol/L


V = (0.0012531mol)(0.0821 L atm/K mol)(310K)/(1.00atm)
=0.0318926481 L
=31.8926481 mL
"or 31.89mL"

Originally Posted by sacredsarcasm

first of all the assumption you made is incorrect. 1 mL or N2 gas is not equal to 1 g of N2 gas. but you are on the right track.

I would go along these lines. Using P1/n1=P2/n2 we can conclude that this amount of gas would go from the .0012531 at 4atm to .0004177 at 1 atm. thus the amount of N2 gas released would be the difference of this... or 0.0012531 mol/L.

now you can use the ideal gas law to find the volume. PV=nRT

(1.0)(x)=(0.0012531)(0.082)(310)
x=0.03189L
or 31.89mL

You win, although I think you meant "from the .0016708 at 4atm to .0004177 at 1 atm. thus the amount of N2 gas released would be the difference of this... or 0.0012531 mol/L."

Originally Posted by draco7891

Draco was asleep for this discourse, but took upon himself to have a stab at it over morning crap.

Slightly different approach than sacred's, let's see if it holds water (*rimshot*).


Answer is in units of volume, so solve PV = nRT for V, V = nRT/P.

We know:

0.0016708 mol/L @ 4 atm

and, doing a little multiplication: 0.0005355 mol/L @ 1 atm.

We're taking a gas under 4 atm of pressure and reducing it to 1 atm, so only a portion comes out of solution (the rest remaining to maintain saturation in the solution). Further, we can assume that we're working with 1L solution's worth of gas, therefore we subtract:

0.0016708 - 0.0005355 = 0.00113528 mol

And then we solve our ideal gas equation:

(0.00113528 mol)(0.0821 atmL/molK)(310 K)/(1 atm) = 0.02889393 L, or 28.89393 mL gas will come out of solution, per L of solution.

Draco

PS: The difference may be in rounding errors in the given numbers or whathave you. We're within 10%. Claim atmospheric variance and throw yourself on the mercy of the court, AFAIAC.

You won (not really, you had the wrong numbers) ... but... you should have just used my previous 1atm mol/L number instead of trying to recalculate it BECAUSE somewhere along the line, your math got off, instead of the mol being 0.0016708 - 0.0004177, you had 0.0016708 - 0.0005355. Which put it off, just that much...



THANKYOU EVERYONE WHO HELPED WITH THIS, YOU GUYS ARE GREAT! (not you bunni!)