Question 1: What is the molar solubility of AgBr in 1.0 L of water? For AgBr, Ksp = 5 x 10-13. Give your answer in moles per litre, accurate to two significant figures. Do not include units as part of your answer. (Enter 1.23x10-5 as 1.23e-5.)
Question 2: What is the molar solubility of PbCl2 in 1.0 L of water? For PbCl2, Ksp=1.7x10-5. You may assume that the ions do not form ion pairs in solution. Give your answer in moles per litre, accurate to two significant figures. Do not include units as part of your answer. (Enter 1.23x10-5 as 1.23e-5.)
Question 3: What is the pH of a saturated solution of Mn(OH)2 at 25oC? For Mn(OH)2, Ksp = 6.0x10-14. Give three digits in your answer (e.g. 8.47, 12.6, 3.75, etc.)
Question 4: In a particular solution, [Cr3+] = 7.9x10-3 mol/L. What is the minimum pH at which Cr(OH)3(s) will precipitate from this solution? Assume the temperature is 25oC. For Cr(OH)3(s), Ksp = 6.3x10-31 at 25oC. Give your answer with three digits (e.g. 8.74, 12.1, 3.17, etc.)
Question 5: A solution has [Cl-] = 0.033 mol/L and [I-] = 0.081 mol/L. Finely divided, solid Pb(NO3)2 is slowly added to the solution with stirring.
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Salt
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Ksp
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PbCl2
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1.6x10-5
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Pbl2
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7.1x10-9
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What are [Pb2+], [Cl-] and [I-] at the instant the second precipitate just begins to form? Enter your answers with 2 significant figures.
[Pb2+] = ____________ mol/L
[Cl-] = ____________ mol/L
[I-] = ____________ mol/L
Question 6: The overall formation constant for Cu(NH3)42+ is 1.1x1013 at 25oC. What is [Cu2+], in moles per litre, at equilibrium when 7.3 g Cu(NO3)2 is dissolved in 0.500 L of 1.00 mol/L NH3(aq)? Assume that there is no volume change when the Cu(NO3)2 is added to the solution.
Give your answer accurate to two signficant figures. Enter 1.23x10-10 as 1.23e-10. Give your answer in mol/L but do not include units as part of your answer.
Molar masses (in g/mol)
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N, 14.01
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O, 16.00
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Cu, 63.55
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Assume that Cu2+ + 4NH3 --> Cu(NH3)42+ is the only important reaction.