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1. Calculate the following for the given aqueous solutions at 25 degrees celsius

ID: 522225 • Letter: 1

Question

1. Calculate the following for the given aqueous solutions at 25 degrees celsius

a. the [OH-] concentration of a Sr(OH)2 solution whose pH is 13.55

b. the pH of a 2.225 M Ba(OH)2 solution

2. At 25 degrees Celsius what would be the pH of 50.00 mL of an aqueous 0.250 M lactic acid (monoprotic) solution that has had 26.25 mL of 0.200 M KOH added to it? The Ka of lactic acid = 1.38 x 10^-4

3. Calculate the Ksp of Ca3(PO4)2 at 20.0 degrees Celsius if its Molar Solubility is known to be 1.10 x 10^-7 M at this temperature

4. What is the solubility of vanadium (III) hydroxide (MM= 101.963 g/mol) in g/100 mL at 20 degrees Celsius. The Ksp of V(OH)3 = 4.10 x 10^ -35 at this temperature

Explanation / Answer

1)

a) pH = 13.55

pH + pOH =14

pOH = 0.45

[OH-] = 10^-pOH

[OH-] = 10^-0.45

[OH-] = 0.355 M

b)

2.225 M Ba(OH)2

[OH-] = 2 x 2.225 = 4.45 M

pOH = -log [OH-]

pOH = 0.648

pH + pOH = 14

pH = 13.35