Question

The mass of cobalt(II) hydroxide that is dissolved in 150 mL of a saturated solution is ES

Answer 1

oo Condition of precipitation Consider ionic product (kip) similar to reaction quotient Q in chemical equilibrium. For precipitation, ionic product (KIP) should be greater than solubility product Ksp. This will make the equilibrium of undissolved salt and dissolved salt shift in backward direction leading to precipitation. After precipitation, solution will become saturated and Kip = Ksp. Remember to modify the concentration of the precipitating ions because of volume change occouring upon mixing both solutions. oo

Ksp = 1x10-15 S- folobility Colomly 3 (0,4 + 2042 aq) S PS Kape [602+1(04-)2 - s (23)2" s kep= 453 1810-15 = 4x53 S- (4x10-15) '3 m S = 6.3 *10-6M] Volume lvl = 150 ml - 150X10-32 * Volume (int) So, Mole of calortly = molavity loe. Solubility 151 : 63x10-6 x 150 x 10-3 -9.45x107m09 molar mass color = 92.948 gominol - so coloola mass of dysolved = mols x molar mars - 9045410-7 molx 99.948 gmined = 8.78 x 10-5 gm = 78.78X10-5 gm?