Assume that the molal freezing point depression constant of water is 1.86 degree

Question

Assume that the molal freezing point depression constant of water is 1.86 degrees celsius kg/mol and that the freezing point of water is 0.00 degrees celsius. A. Complete the following reaction showing what ions calcium chloride will produce upon dissolving in water: CaCL2(aq) --> b. Calculate the molarity (in m) of all solutes (that is, all ions in this problem) of .015 m calcium chloride aqueous solution. C. Calculate both the freezing point depression ( ? T ) and the freezing point of 0.15m calcium chloride aqueous solution.

Explanation / Answer

a) CaCl2 (aq)---------------------> Ca^+2(aq) + 2 Cl^-1(aq)

CALICIUM CHLORIDE ON DISSOCIATION IN WATER GIVES CALICIUM ION(Ca^=2) AND two CHLORIDE IONs (Cl^-1)

b) molarity= molality[[1000*density)-(molarity*molecular weight of the solute)/[1000]

     molarity=0.15[(1000*2.15)-(M*101)]/1000

MOLARITY=0.327 MOLAR

MOLARITY OF CALCIUM IOS= 0.327M

MOLARITY OF CHLORIDE IONS= 2*0.327=0.654M

c)T0-Ts= kf*m

    0-Ts= 1.86*0.15

Ts= -0.279^0c

freezing point of the solution= -0.279 ^0centigarde

DTf To-Ts=0-(-0.279) = 0.279 degree centigrade

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