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mickey4 mickey4
wrote...
Posts: 30
Rep: 1 0
9 years ago
An aqueous CaCl2 solution has a vapor pressure of 81.0mmHg  at 50 ∘C. The vapor pressure of pure water at this temperature is 92.6 mmHg. What is the concentration of CaCl2 in mass percent?
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rsb
wrote...
9 years ago
An aqueous CaCl2 solution has a vapor pressure of 83.5 mmHg at 50 C. The vapor pressure of pure water at this temperature is 92.6 mmHg. What is the concentration of CaCl2 in mass percent? Please provide formula used and some details. Thanks.

Answer:

83.5 = 92.6 X
X = moles fraction water =0.902 = moles water / moles water + moles CaCl2

1 - 0.902 = 0.098 = moles CaCl2 / moles CaCl2 + moles water
wrote...
9 years ago
An aqueous CaCl2 solution has a vapor pressure of 84.0 mmHg at 50 degrees C. The vapor pressure of pure H2O at this temperature is 92.6 mmHg. What is the concentration of CaCl2 in mass percent?

Answer:

p(total) = 176.6 mmHg
x(water) = 84/176.6 = 0.48
x(cacl2) = 1-0.48 = 0.52

n(water) = n(total)*x(water)
n(cacl2) = n(total)*x(cacl2)

%mass(cacl2) = 100 * (mass(cacl2)/mass(total))
mass(cacl2)= n(cacl2)*M(cacl2)
mass(water)=n(water)*M(water)
mass(total)=m(water)+m(cacl2)

n(water)/n(cacl2)= 0.92
m(w)/m(cacl2) = 0.92 * (18/111) =0.15
m(w) = 0.15*m(cacl2)

m(total) = 0.15cacl2 + cacl2 = 1.15cacl2
(1/1.15)*100 = %86.96
Answer accepted by topic starter
doubleudoubleu
wrote...
Posts: 440
9 years ago
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aera20162020
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mickey4 Author
wrote...
9 years ago
Thank you!
wrote...
3 years ago
Thank you
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