Why Is Aluminiums Boiling Point Much Higher Than That Of Magnesium?
I know that Al unlike Mg has one electron in its 3p subshell so why would this increase its boiling point? Thanks!
3 comments May 12th, 2009
Posts filed under 'Colligative Properties of Solution'
If Methyl Alcohol Boils At 84 Degrees On The Hyde Scale, What Is Its Boiling Point On The Jekyll Scale?
On a new Jekyll temperature scale, water freezes at 17 degrees and boils at 97 degrees. On another new temperature scale, the Hyde scale, water freezes at 0 degrees and boils at 120 degrees.
Heres the question, How do I figure this out???
If methyl alcohol boils at 84 degrees on the Hyde scale, what is its boiling point on the Jekyll scale?
2 comments May 12th, 2009
How to calculate the vapor pressure of the water in the urea solution?
Chemistry Tutor Site - Chemistry Homework Help
A 650 ml aqueous solution contains 70 g of urea CO(NH2)2. The vapor pressure of pure water at 20.0 degrees C is 17.5 mm Hg. What is the vapor pressure of the water in the urea solution? (assume that the molar concentration of water in this solution is 55.5 M)
Chemistry Tutor Site - Chemistry Homework Answer
Moles urea = 70 g /60.07 g/mol =1.17
Moles water = 55.5 x 0.650 L =36.1
Mole fraction water = 36.1 / 36.1 + 1.17 =0.969
p = p°X = 17.5 x 0.969 = 17.0 mm Hg
Add comment October 14th, 2008
Calculation Involve of Vapor Pressure
Chemistry Tutor Site - Chemistry Homework Help
At 20˚C the vapor pressure of benzene is 75 torr, and the vapor pressure of toluene is 22 torr.
(a) A solution is prepared from 1.0 mole of biphenyl, a nonvolatile solute, and 49.0 moles of benzene. How do I calculate the vapor pressure of the solution at if the temp. is at 20˚C.
(b)A second solution is prepared from 3.0 moles of toluene and 1.0 mole of benzene. How do I determine the vapor pressure of this solution and the mole fraction of benzene in the vapor?
Chemistry Tutor Site - Chemistry Homework Answer
(a) From Raoult’s law: Vapour pressure = mole fraction in liquid * SVP
For benzene:
Vapour pressure = 49/(1+49) * 75 = 73.5 torr
The biphenyl is involatile so its vapour pressure is 0 torr.
Vapour pressure of solution = 0 + 73.5 = 73.5 torr
b) Using the same equation:
For toluene:
Vapour pressure = 3/(3+1) * 22 = 16.5 torr
For benzene:
Vapour pressure = 1/(3+1) * 75 = 18.75 torr
Vapour pressure of solution = 16.5 + 18.75 = 35.25 torr
Now, using Dalton’s law:
Partial pressure = mole fraction in vapour phase * total pressure
Mole fraction = Partial pressure / total pressure = 18.75 / 35.25 = 0.532
Add comment October 14th, 2008