1) A saline solution contains 8.4 g of NaCl in 1.00 kg of water. Assuming an ide

Question

1) A saline solution contains 8.4 g of NaCl in 1.00 kg of water. Assuming an ideal value for the Van't Hoff factor, i, calculate the freezing point of this solution in oC.

2)
At what angle (in degrees) does first-order diffraction from layers of atoms 260.2 pm apart occur, using x rays with a wavelength of 145 pm?

3)Ar is a solid below -189 oC with a face-centered cubic array of atoms and a supposed density of 1.32 g/cm3. Assuming that the atoms are spheres in contact along the face diagonal, what is the radius of a Ar atom (in Angstroms)? An angstrom = 10-10 m or 10-8 cm. Hint, first find the length of an edge of the unit cell. (Argon's actual density is 1.65 g/cm3.)

Explanation / Answer

1) molality of solution = (8.4/58.5)*(1/1) = 0.1436 molal

I = vanthoff factor = 2

Kf of water = 1.86 c.kg/mol

DTf = i*Kf*m

0-T = 2*1.86*(0.1436)

T = MELTINGPOINT OF SOLUTION = -0.5342 c

2) nL = 2dsino

1*145 = 2*260.2sinx

x = angle =

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.