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The Solution Process. The formation of solutions is a physical change forming a homogeneous mixture. 1. A solution is made up of a solute and a solvent. The solvent does the dissolving. The solute is the substance that is dissolved. The Solution Process.
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The Solution Process • The formation of solutions is a physical change forming a homogeneous mixture. 1
A solution is made up of a solute and a solvent. The solvent does the dissolving. The solute is the substance that is dissolved. The Solution Process
Some things dissolve easier in one kind of substance as opposed to another. Sugar dissolves easily in water and oil does not. Water has a low solubility when it comes to oil. Since oil is not soluble in water, it will never truly dissolve. The Solution Process
A solute will dissolve in a solvent if the solute-solvent forces of attraction are great enough to overcome the solute-solute and solvent-solvent forces of attraction. A solute will not dissolve if the solute-solvent forces of attraction are weaker than individual solute and solvent intermolecular attractions. The Solution Process
“Like dissolves like.” The expression means that dissolving occurs when similarities exist between the solvent and the solute. The Solution Process
Water is polar, while C6H14 and CCl4 are nonpolar. As a result, neither substances will dissolve in water. The Solution Process
Solubility The maximum quantity of the substance, expressed in grams, that will dissolve in a certain solvent at a specific temperature. S-C-9-1_Solubility Presentation
Types of Solutions • Saturated – a solution that contains the maximum quantity of solute that dissolves at that temperature. • Unsaturated– a solution that contains less than the maximum amount of solute that can dissolve at a particular temperature. • Supersaturated – a solution that contains more solute than a saturated solution. • Supersaturated solutions can be attained by heating the solution up to dissolve more solute at that higher temperature and then letting the solution cool. • Once cooled, agitation causes crystals to precipitate (separate from solution) out of the super saturated solution. S-C-9-1_Solubility Presentation
UNSATURATED SOLUTION more solute can dissolve SUPERSATURATED SOLUTION becomes unstable, crystals form SATURATED SOLUTION no more solute can dissolve at given temperature increasing concentration
Solubility and TemperatureIncreasing the temperature of a solvent speeds up the particle movement. This causes more solvent particles to bump into the solute, resulting in solute particles breaking loose and dissolving faster.Solubility CurveA graph of the solubility of a compound (grams/100 grams water on the Y-axis) at various temperatures (Celsius on X- axis). Each compound has a different curve. S-C-9-1_Solubility Presentation
gases solids Solubility vs. Temperature for Solids Solubility Curve Graph *Solubility is dependent on temperature What trends do you see on the graph? How is the solubility of gases and solids different? 140 KI 130 120 NaNO3 110 100 KNO3 90 80 HCl NH4Cl 70 Solubility (grams of solute/100 g H2O) 60 NH3 KCl 50 40 30 NaCl KClO3 20 10 SO2 0 10 20 30 40 50 60 70 80 90 100 Temperature °C
gases solids If you stir faster, will that make you dissolve more?No, it allows you to dissolve substances faster but not more. Increasing the temperature does allow you to dissolve more. Solubility vs. Temperature for Solids 140 KI 130 120 NaNO3 110 100 KNO3 90 80 HCl NH4Cl 70 Solubility (grams of solute/100 g H2O) 60 NH3 KCl 50 40 30 NaCl KClO3 20 10 SO2 0 10 20 30 40 50 60 70 80 90 100 Temperature
Solubility vs. Temperature • What term describes 39g NaCl at 70C? Saturated! • What about 30g at the same temperature? Unsaturated • What about 45g at the same temperature? Supersaturated
Sol. Sol. To To Solids dissolved in liquid Gases dissolved in liquids As Tosolubility As To solubility • Solids are more soluble at...higher temperatures. • Gases are more soluble at...lower temperatures & • higher pressures.
Solubility of Sodium Acetate 150 Saturated Supersaturated solution 100 Solubility(g/100 g H2O) Unsaturated solution 50 0 25 50 75 100 Temperature (oC)