[mo_1984]

1.   If the concentration of Pb2+ is found to be 2.3 x 10-9 mol/L in a saturated solution of Pb3(PO4)2, what is the Ksp of Pb3(PO4)2 ?
   

2.   What mass of Ag2CO3 would be found in 1.4 L of a saturated solution if the Ksp of Ag2CO3 is 8.2 x 10-12?
   

3.   A solution of AgNO3 (45 mL/0.45 M) was mixed with solution of NaCl (85 mL/1.35 x 10-2 M)
a) Calculate the ion product of the potential precipitate.
b) Would a precipitate form? The Ksp of AgCl(s) is 1.8 x 10-10.
   

4.   Find the temperature at which the reaction below is spontaneous given this data:
Hfo of NH3(g) = - 46 kJ/mol, So of NH3(g) = 192.5 J/mol·K, So of N2(g) = 191.5 J/mol·K,
So of H2(g) = 130.6 J/mol·K.
N2(g) + 3H2(g) ßà 2NH3(g)
   

5.   What is the concentration of a weak base if its Kb = 1.4 x 10-11 and its pH = 8.75?
   

6.   A weak base with a concentration of 1.3 mol/L has a percent ionization of 0.72%. What is the Kb of this weak base?
   

7.   What is the percent ionization of a 1.38 mol/L weak acid if its Ka = 2.7 x 10-6? Answer to two (2) decimal places.
   

8.   What is the pH of a 1.24 mol/L solution of HCN(aq) if its Ka = 6.2 x 10-10?
   

9.   25 mL of standardized 0.45 mol/L NaOH is titrated with 21 mL of 0.35 mol/L acetic acid. Calculate the pH of the solution.
   

10.   24 mL of 0.39 mol/L acetic acid is titrated with a standardized 0.33 mol/L KOH solution. Calculate the pH of the solution after 17 mL of the KOH solution has been added. Assume the Ka of acetic acid is 1.8 x 10-5.

[AWK]

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[mo_1984]

i have two different answer sheets and don't have enough time to type the answers but i keep getting different answer every time i do the same question.

for nmber 1) Ksp = (3x)^3 (2x)^2 = (Pb)(PO4)
= (2.3 X 10^-9)^3 (2.3 X 10^-9)^2 = 5.29 X 10 ^-18.
Just to prove i have the answers but i believe that it may not be right. It is 1 at night and the test is due at 3.

[mo_1984]

Can someone please help me.... i m tryin my best and i want to see if my answers match with the method T

[AWK]

2.3 X 10^-9 is a molarity of Pb²⁺ but not the molarity of Pb₃(PO₄)₂ in solution. Your result is 60.75 times higher than the correct one.