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Crystallization After a while, solute particles which are already dissolved begin to collide with un- dissolved particles, returning them to solid
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Solubility
Dissolving• Particles of the solute move
into the solvent
Crystallization• After a while, solute particles
which are already dissolved begin to collide with un-dissolved particles, returning them to solid
• As more particles dissolve, more particles crystallize until EQUILIBRIUM is reached
Equilibrium• The rate where particles
dissolve equals the rate where particles crystallize. • When equilibrium is reached
un-dissolved solute remains visible no matter what
Saturated Solution• no more solute will dissolve• max amount of solute at a
particular temperature• particles dissolve and crystallize
but the concentration remains the same
Supersaturated Solution
• a substance that has been heated to dissolve additional solute and then carefully cooled (more than saturated)
Qualitative Solubility• relative
solubility in terms of soluble, low solubility or insoluble
Quantitative Solubility• The concentration of a solute
in a saturated solution at a given temperature• # of moles of solute needed to
form 1 litre of saturated solution at a specified temp.
• Solubility of a saturated solution- aka molarity
- aka concentration
Example
• A saturated solution produced by dissolveing hydrogen chloride gas in water is called concentrated hydrochloric acid. If 46.5g of hydrogen chloride gas is required to prepare 100mL of concentrated hydrochloric acid at 25C, what is the solubility of hydrogen chloride at 25C?
mol/L = HCl
Factors that Affect Solubility
• Temperature• temperature
(energy) increases the solubility
• temp decreases the solubility of gases
• Pressure• Increasing the
pressure of gases increases the solubility • no effect on
liquids or solids
• Nature of Solute and Solvent• Depends on the nature of the
bonds (polar and non polar)• i.e. grease will dissolve in gas
but not in water
Precipitates• 2 aqueous solutions combine &
the positive ion (cation) of one combines with the negative ion (anion) of the other to form an insoluble compound (a solid precipitate)
•Write the net ionic equation and use a solubility table to determine whether a solid will form
Example
• Write the net ionic equation for the formation of a precipitate when aqueous solution of potassium hydroxide and magnesium chloride are mixed
• 2KOH(aq) + MgCl2(aq) 2KCl(?) + Mg(OH)2(?)
• Total ionic equation
• Net ionic equation