102 - Physical Chemistry Questions Answers

boiling point elevation = (-32.7) - (-33.4) = 0.7

now according to the given data 

boiling point elevation = 1000*K(ammonia)*1/1 = 1000*0.00035 = 0.35

so i = 0.7/0.35 = 2

so 100 % dissociation

E_cell = E_C - E_A - (0.0591/1) logs

on taking the values 0.29 = -0.0591 logs

or  logs = -0.29/0.0591 = -4.907

now K_sp = s²

so logK_sp = 2logs = -9.8

we know that  dT = K_fm so m = 10/1.86

m means moles of ethelene glycol in 1000 gm water

so 1000 gm water contains (10/1.86) * 62 gm ethylene glycol

so 1000 cc water contains [(10/1.86)* 62] / 1.12 cc

now calculate

10.1 g of a volatile liquid occupies a volume of 4 litres when vaporised at 100 C and 70 cm pressure.

first convert this volume to STP by using the formula P₁V₁/T₁ = P₂V₂/T₂

after getting the value of  V₂ , we can say that V₂ volume contains 10.1 gm so 22.4 litre will contain 10.1*22.4/V₂

thus we will get molar mass

now use πV = (w/M) RT

V = 0.1 litre, w = 2 gms, M = calculated above, T = 273 K

x22+(1-x)75 = 50 

so 22x+75-75x = 50

so 53x = 25 so x = 25/53

so ratio of there amounts (in mole) = 25/53 : 28//53    =  25:28

now ratio in vapour form can be obtained by this method

v. p. of pure benzene = 25/53 * 22 = 550/53

and v. p. of pure toluene = 28/53 * 75 = 2100/53

so ratio = (550/53)/(2100/53) = 550/2100 = 55/210 = 11/42

In Diamond, there is 8 lattice points per unit cell.  The maximum radius that a hard sphere can have is , r and a are in their usual meaning, Hence the packing fraction is:

second, third and fourth coordination number means to count the no. of atoms of either Cl or Na, having second, third and fourth closest distance

for NaCl         first coordination number =    6   (6 faces)            distance (a/2)

                 second coordination number =  12   (12 edges)        distance (a/√2)

                       third coordination number =    8   (8 corners)        distance (a√3/2)

                    fourth coordination number =    6    ( 6 centre)          distance (a)

similarly try for others

according to the given conditions

along the face of a side 4x = 400√2             or  x = 100√2                 here x is radius of the atom forming lattice

and along an edge 2x+2y = 400                      here y is interstitial radius

so y = 200-x = 200-100√2  = 100 (2-1.414) = 100(0.586) = 58.6 pm

so diameter = 117.2

use the formula d = Mn/N₀a³

calculate a?                here n = 1

now 2r ^- + 2r ⁺ = a √3

and 2r ^- = a

divide these equations for getting ratio

B atom forms ccp, let No. of atoms of B = 1

no. of tetrahedral voids = 2

but formula given is A_2/3B

so % of voids occupied = (2/3)*100/2 = 33.34 %