Chemistry 12
Worksheet 3.1
Solubility Product Calculations
1.
Write the Ksp expression for these compounds.
a)
FeS
e)
PbI2
b)
Bi2S
f)
Cu(OH)2
c)
Ag2CO3
g)
PbCrO4
d)
Al(OH)3
h)
Sb2S3
2.
Why are solids left out of the Ksp expression?
3.
Barium sulphate, BaSO4, is so insoluble that is can be swallowed without significant
2+
danger, even though Ba is toxic. At 25 °C, 1.00 L of water dissolves only 0.00245 g of
BaSO4.
a)
How many moles of BaSO4 dissolve per liter? 1.05 × 10–5 mol
b)
c)
4.
What are the molar concentrations of Ba
1.05 × 10–5 M
Calculate Ksp for BaSO4. 1.10 × 10–10
2+
2–
and SO4 in a saturated solution?
Magnesium hydroxide, Mg(OH)2, found in milk of magnesia, has a solubility of
–3
7.05 × 10 g/L at 25 °C.
a)
What is the solubility expressed in mol/L? 1.21 × 10–4 M
2+
–
b)
What are the Mg and OH concentrations in mol/L? 1.21 × 10–4 M,
2.42 × 104M
c)
Calculate Ksp for Mg(OH)2. 7.07 × 10–12
–5
5.
At 25 °C the molar solubility of Ag3PO4 is 1.8 × 10
2.8 × 10–18
mol/L. Calculate Ksp for this salt.
6.
A salt whose formula is of the form MX has a value of Ksp equal to 2.0 × 10 . Another
slightly soluble salt, MX3, has to have what value of Ksp if the molar solubilities of the
two salts are identical. 1.1 × 10–18
7.
A salt whose formula of the type M2X3 has Ksp = 1.0 × 10 . Another salt, M2X has to
have what Ksp value if M2X has twice the molar solubility of M2X3? 1.9 × 10–12
8.
The molar solubility of Ba3(PO4)2 is 1.4 × 10
5.8 × 10–38
–10
–20
WS3.1 Ksp & TIP Calcs.doc
–8
mol/L. Calculate Ksp for this salt.
1
Chemistry 12
Worksheet 3.1
–5
9.
Calcium sulphate is found in plaster. At 25 °C the value of Ksp for CaSO4 is 2.4 × 10 .
What is the solubility of CaSO4 expressed in mol/L? 4.9 × 10–3 M
10.
Chalk is CaCO3, and at 25 °C its Ksp = 4.5 × 10 . What is the molar solubility of
CaCO3? How many grams of CaCO3 dissolve in 100 mL of water? 6.7 × 10–4 g/100 ml
11.
Calculate the molar solubility of lead iodide, PbI2 (Ksp = 7.9 × 10 ). 1.2 × 10–3 M
12.
What is the molar solubility of Ag2CO3 at 25 °C (Ksp = 8.1 × 10
13.
What is the trial ion product when equal volumes of 0.060 M AgNO3 and 0.00090 M
NaBrO3 are mixed? 1.4 × 10–5
14.
Will a precipitate form when 20.0 mL of 0.0060 M CaCl2 and 20.0 mL of 0.0050 M
Na2SO4 are mixed together? TIP = 7.5 × 10–6 < Ksp = 7.1 × 10–5 => NO PPT
15.
Will a precipitate form when 85.0 mL of 1.00 × 10–2 M Cu(NO3)2 and 25.0 mL of
1.00 × 10–2 M NaIO3 are mixed? Explain using appropriate calculations. TIP = 4.0 × 10–
8
< Ksp = 6.9 × 10–8 => NO PPT
16.
At 25°C, will a precipitate form when 65.0 mL of 0.015 M Pb(NO3)2 is combined with
45.0 mL of 0.015 M NaI? Support your answer with calculations. TIP = 3.3 × 10–7 > Ksp
= 8.5 × 10–9 => PPT
17.
What is the maximum [Sr2+] that can exist in a solution of 0.10 M Na2SO4 ? 3.4 × 10–6
18.
Calculate the maximum moles of Br– that can exist in 0.500 L of 0.10 M Pb(NO3)2 .
4.1 × 10–3 mol
19.
A solution of AgNO3 is slowly added to a mixture containing 0.10 M I– ,Cl– ,Br– and
IO3–. Which precipitate forms first? Explain. I–, requires lowest concentration of Ag+ to
ppt (8.5 × 10–16)
20.
A solution of Pb(NO3)2 is slowly added to a mixture containing 0.10 M SO42–, I– and Cl–.
Which precipitate forms first? Explain. SO42–, requires the lowest concentration of Pb2+
to ppt (1.8 × 10–7)
20.
A container is filled with 10.0 L of 0.075 M NaI. Calculate the maximum mass of solid
Pb(NO3)2 that can be dissolved without forming a precipitate. 5.0 × 10–3 g
21.
A maximum of 0.60 g Pb(NO3)2 can be added to 1.5 L of NaBr(aq) without forming a
precipitate. Calculate the [NaBr]. 7.4 × 10–2 M
22.
Calculate the minimum mass of Pb(NO3)2 required to start precipitation in 65.0 mL of
0.115 M ZnI2. 3.45 × 10–6 g
–9
–9
–12
WS3.1 Ksp & TIP Calcs.doc
)? 1.3 × 10–4 M
2