To interconvert the concentration units molality (m) and mass percent, you must also know the density of the solution. A) True B
1 answer:
Answer:
The correct answer is option false.
Explanation:
Molality of the solution defined as moles of substance present in 1 kilogram of solvent.
Moles =
Mass of percent (w/w%) of the solution is defined as amount of solute present in 100 grams of solution.
So, if want to inter-convert molality into mass percent we can do that without knowing density of solution.
Mass of solution = Mass of solute + Mass of solvent
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Answer:
Molar mass of solute: 300g/mol
Explanation:
<em>Vapor pressure of pure benzene: 0.930 atm</em>
<em>Assuming you dissolve 10.0 g of the non-volatile solute in 78.11g of benzene and vapour pressure of solution was found to be 0.900atm</em>
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It is possible to answer this question based on Raoult's law that states vapor pressure of an ideal solution is equal to mole fraction of the solvent multiplied to pressure of pure solvent:
Moles in 78.11g of benzene are:
78.11g benzene × (1mol / 78.11g) = <em>1 mol benzene</em>
Now, mole fraction replacing in Raoult's law is:
0.900atm / 0.930atm = <em>0.9677 = moles solvent / total moles</em>.
As mole of solvent is 1:
0.9677× total moles = 1 mole benzene.
Total moles:
1.033 total moles. Moles of solute are:
1.033 moles - 1.000 moles = <em>0.0333 moles</em>.
As molar mass is the mass of a substance in 1 mole. Molar mass of the solute is:
10.0g / 0.033moles = <em>300g/mol</em>