What is the solubility in moles/liter for magnesium hydroxide at 25 oC given a Ksp value of 1.1 x 10-11. Write using scientific notation and use 1 or 2 decimal places (even though this is strictly incorrect!)

S = 0.00014 moles /L = 1.4 * 10^-4 moles/L

Explanation:

Step 1: Data given

Temperature = 25.0 °C

Ksp = 1.1 * 10^-11

Step 2: The balanced equation

Mg(OH)2(s) ⇆ Mg^2+(aq) + 2OH-(aq)

Step 3: Define Ksp

[Mg(OH)2 = 1.11 * 10^-11 = S

[Mg^2+] = S

[OH-] = 2S

Ksp = [Mg^2+]*[OH-]²

Ksp = S * (2S)²

1.1 * 10^-11 = 4S³

S³ = 2.75 * 10^-12

S = 0.00014 moles /L

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm