factors affecting solubility
Post on 31-Dec-2015
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Factors Affecting Solubility
What is Solubility?• Describes the amount of solute that dissolves
in a solvent.
Driving Forces of SolubilityEnthalpy:
• Total energy of a chemical system• The enthalpy change (∆H) is the
amount of heat released or absorbed when a chemical reaction occurs
at constant pressure.
Driving Forces of SolubilityEntropy:
• Randomness• Things like to become more random.
Entropy
*Entropy increases as a substance changes from solid to liquid to gas
When a solid dissolves, attractive forces are weakened, and randomness increases.
As ice melts, entropy increases
*If exothermic (gives off heat), dissolving takes place.
*Endothermic (absorbs heat) can occur if randomness term is greater.
Youtube Video - Dissolving in Endothermic Reaction
Temperature and SolubilityAbout 95% of solids are most soluble at high
temperatures.
Solids = direct relationship for temperature and solubility
Temperature and SolubilityGases have no crystal lattice energy.
Dissolving of a gas is generally exothermic, and favored at lower temperatures.
Gases = indirect relationship for temperature and solubility
Pressure and SolubilityPressure only affects the solubility of gases.
As air pressure increases, solubility of a gas increases.
Pressure and Carbonation Video
DirectRelationship
Nature and SolubilityWhether polar or nonpolar.
*Like dissolves like
The rule of thumb is that "like dissolves like". Polar/ionic solvents dissolve polar/ionic solutes and non-polar solvents dissolve non-polar solutes.
Water Dissolving Salt Video
Oil Dissolution Video
Oil In Water Video
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