1. Precipitation reactions
Chapter 4.2
Precipitation reactions
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2. LecturePLUS Timberlake
Solubility
The maximum amount of solute that can dissolve in a specific amount of solvent usually 100 g.
g of solute
100 g water
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3. Saturated and Unsaturated
A saturated solution contains the maximum amount of solute that can dissolve.
Undissolved solute remains.
An unsaturated solution does not contain all the solute that could dissolve
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4. LecturePLUS Timberlake
Learning Check S1
At 40C, the solubility of KBr is 80 g/100 g H2O. Indicate if the following solutions are
(1) saturated or (2) unsaturated
A. ___60 g KBr in 100 g of water at 40C
B. ___200 g KBr in 200 g of water at 40C
C. ___25 KBr in 50 g of water at 40C
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5. LecturePLUS Timberlake
Solution S1
At 40C, the solubility of KBr is 80 g/100 g H2O. Indicate if the following solutions are
(1) saturated or (2) unsaturated
A. 2 Less than 80 g/100 g H2O
B. 1 Same as 100 g KBr in 100 g of water
at 40C, which is greater than its solubility
C. 2 Same as 60 g KBr in 100 g of water,
which is less than its solubility
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6. Temperature and Solubility of Solids
Temperature Solubility (g/100 g H2O)
KCl(s) NaNO3(s) 0°
20°C
50°C
100°C
The solubility of most solids (decreases or increases ) with an increase in the temperature.
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7. Temperature and Solubility of Solids
Temperature Solubility (g/100 g H2O)
KCl(s) NaNO3(s) 0°
20°C
50°C
100°C
The solubility of most solids increases with an increase in the temperature.
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8. Temperature and Solubility of Gases
Temperature Solubility (g/100 g H2O)
CO2(g) O2(g)
0°C
20°C
50°C
The solubility of gases (decreases or increases) with an increase in temperature.
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9. Temperature and Solubility of Gases
Temperature Solubility (g/100 g H2O)
CO2(g) O2(g)
0°C
20°C
50°C
The solubility of gases decreases with an increase in temperature.
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10. LecturePLUS Timberlake
Learning Check S2
A. Why would a bottle of carbonated drink possibly burst (explode) when it is left out in the hot sun ?
B. Why would fish die in water that gets too warm?
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11. LecturePLUS Timberlake
Solution S2
A. Gas in the bottle builds up as the gas becomes less soluble in water at high temperatures, which may cause the bottle to explode.
B. Because O2 gas is less soluble in warm water, the fish may not obtain the needed amount of O2 for their survival.
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12. Soluble and Insoluble Salts
A soluble salt is an ionic compound that dissolves in water.
An insoluble salt is an ionic compound that does not dissolve in water
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13. LecturePLUS Timberlake
Solubility Rules
1. A salt is soluble in water if it contains any one of the following ions:
NH4+ Li Na K+ or NO3-
Examples:
soluble salts
LiCl Na2SO KBr Ca(NO3)2
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14. LecturePLUS Timberlake
Cl- Salts
2. Salts with Cl- are soluble, but not if the
positive ion is Ag+, Pb2+, or Hg22+.
Examples:
soluble not soluble(will not dissolve)
MgCl2 AgCl
PbCl2
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15. LecturePLUS Timberlake
SO42- Salts
3. Salts with SO42- are soluble, but not if the positive ion is Ba2+, Pb2+, Hg2+ or Ca2+.
Examples:
soluble not soluble
MgSO4 BaSO4
PbSO4
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16. LecturePLUS Timberlake
Other Salts
4. Most salts containing CO32-, PO43-, S2- and OH- are not soluble.
Examples:
soluble not soluble
Na2CO3 CaCO3
K2S CuS
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