A 500 mL saturated solution of MgCO3 (MM =84.3 g/mol) is reduced to 120 mL by evaporation. What mass of solidMgCO3 is formed? Ksp = 4.0 x 10-5for MgCO3.
EDIT: If ions can evaporate in water then the answer below isright. If not, this is how I solved the problem.
MgCO3 dissolves at a 1:1 ratio, thereforeKsp=s2 and s=Ksp1/2 (orsqrt of Ksp)
s = (4.0x10-5)1/2 = .00632 M
Using the equationM1V1=M2V2
M1 = s = 0.00632; V1 = 0.500; V2 = 0.120
Solving for M2 = 0.0263 M
Then multiply M2 by MM to get the mass.
Therefore, mass = (0.0263)(84.3) = 2.22g
Can anyone confirm this?
