Solubility

Chapter 8 Solutions Solubility Percent Concentration Colloids and Suspensions

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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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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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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 LecturePLUS Timberlake

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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 Timberlake its solubility LecturePLUS

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Temperature and Solubility of Solids Temperature 0° 20°C 50°C 100°C

Solubility (g/100 g H2O) KCl(s)

NaNO3(s)

27.6 34.0 42.6 57.6

74 88 114 182

The solubility of most solids (decreases or increases ) with an increase in the temperature. LecturePLUS Timberlake 6

Temperature and Solubility of Solids Temperature 0° 20°C 50°C 100°C

Solubility (g/100 g H2O) KCl(s)

NaNO3(s)

27.6 34.0 42.6 57.6

74 88 114 182

The solubility of most solids increases with an increase in the temperature. LecturePLUS Timberlake

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Temperature and Solubility of Gases Temperature 0°C 20°C 50°C

Solubility (g/100 g H2O) CO2(g)

O2(g)

0.34 0.17 0.076

0.0070 0.0043 0.0026

The solubility of gases (decreases or increases) with an increase in temperature. LecturePLUS Timberlake

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Temperature and Solubility of Gases Temperature 0°C 20°C 50°C

Solubility (g/100 g H2O) CO2(g)

O2(g)

0.34 0.17 0.076

0.0070 0.0043 0.0026

The solubility of gases decreases with an increase in temperature. LecturePLUS Timberlake

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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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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. LecturePLUS Timberlake

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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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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

Na2SO4

KBr

Ca(NO3)2

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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 LecturePLUS Timberlake

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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 LecturePLUS Timberlake

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Other Salts 4. Most salts containing CO32-, PO43-, S2and OH- are not soluble. Examples: soluble

not soluble

Na2CO3

CaCO3

K 2S

CuS LecturePLUS Timberlake

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Learning Check S3 Indicate if each salt is (1)soluble or (2)not soluble: A. ______ Na2SO4 B. ______ MgCO3 C. ______ PbCl2 D. ______ MgCl2 LecturePLUS Timberlake

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Solution S3 Indicate if each salt is (1) soluble or (2) not soluble: A. _1_ Na2SO4 B. _2_ MgCO3 C. _2_ PbCl2 D. _1_ MgCl2 LecturePLUS Timberlake

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