Yahoo Answers: Answers and Comments for In Henry law , Why mole fraction is equal mass of concentration (solution is given in pic)? [Chemistry]
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Sat, 25 May 2019 14:04:03 +0000
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Yahoo Answers: Answers and Comments for In Henry law , Why mole fraction is equal mass of concentration (solution is given in pic)? [Chemistry]
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From pisgahchemist: Partial pressure of ethane
It's a simple ...
https://sg.answers.yahoo.com/question/index?qid=20190525140403AAUPyej
https://sg.answers.yahoo.com/question/index?qid=20190525140403AAUPyej
Sat, 25 May 2019 16:18:06 +0000
Partial pressure of ethane
It's a simple set of ratios:
Case 1 ... P = 1.00 bar, mass of solute = 0.00656g ethane
Case 2 ... P = ??? bar, mass of solute = 0.0500g ethane
P1 / mass 1 = P2 / mass 2
P2 = P1 x mass 2 / mass 1 = 1.00 bar x 0.0500g / 0.00656g = 7.62 bar
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Applying Henry's law:
c = kP ........ c = concentration, k = Henry's law constant, P = partial pressure
k = c / P
k = 0.00656g C2H8 x (1 mol C2H8 / 30.0g C2H8) / 1.00 bar
k = 0.0500g C2H8 x (1 mol C2H8 / 30.0g C2H8) / x bar
both are equal to k, so set them equal
0.00656g C2H8 x (1 mol C2H8 / 30.0g C2H8) / 1.00 bar = 0.0500g C2H8 x (1 mol C2H8 / 30.0g C2H8) / x bar
Cancel out the molar mass and solve for x
0.00656g C2H8 / 1.00 bar = 0.0500g C2H8 / x bar
x bar = 0.0500g / 0.00656g x 1.00 bar
x bar = 7.62 bar
And that's why we can use the ratio of the masses. The molar mass in the conversion to moles cancels out.
As for the answer you posted. The final answer is written to too many significant digits, and it probably contains some roundoff error. It's a bit hard to read, so I'm not sure where the problem in it lies. But clearly, there is more than one way to solve the problem.