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Parts of SolutionsParts of Solutions
Solution-Solution- homogeneous mixture.
SoluteSolute- what gets dissolved. SolventSolvent- what does the
dissolving. SolubleSoluble- Can be dissolved.
Aqueous solutionsAqueous solutions
Dissolved in water. Water is a good solvent
because the molecules are polar.
The oxygen atoms have a partial negative charge.
The hydrogen atoms have a partial positive charge.
HydrationHydration The process of breaking the ions of
salts apart. Ions have charges and attract the
opposite charges on the water molecules.
ElectrolytesElectrolytes
Electricity is moving charges. The ions that are dissolved can
move. Solutions of ionic compounds can
conduct electricity and are called electrolyteselectrolytes. Solutions are classified three ways.
Types of solutionsTypes of solutions
Strong electrolytesStrong electrolytes- completely dissociate (fall apart into ions).
Many ions- Conduct well. Weak electrolytesWeak electrolytes- Partially fall apart
into ions. Few ions -Conduct electricity slightly. Non-electrolytesNon-electrolytes- Don’t fall apart. No ions- Don’t conduct.
Making solutionsMaking solutions
What solute and the solvent are determines• Whether a substance will dissolve.• How much will dissolve.
A solid substance dissolves faster if-
It is stirred or shaken.The particles are made smaller.The temperature is increased.
How Much?How Much? SolubilitySolubility- The maximum amount of
substance that will dissolve at that temperature (usually g/L).
Saturated solutionSaturated solution- Contains the maximum amount of solid dissolved.
Unsaturated solutionUnsaturated solution- Can dissolve more solute.
Supersaturated-Supersaturated- A solution that is temporarily holding more than it can, a seed crystal will make it come out; forms a precipitate
LiquidsLiquids
MiscibleMiscible means the that to liquids can dissolve in each other.
ImmiscibleImmiscible means they can’t
What affects What affects solubility?solubility?
Temperature Pressure The polarity of the solvent
• polar and ionic compounds dissolve in polar solvents such as water
• non-polar solutes dissolve in non-polar solvents such as alcohol
What affects What affects solubility?solubility?
For solids in liquids as the temperature goes up the solubility goes up.
For gases in a liquid as the temperature goes up the solubility goes down.
For gases in a liquid- as the pressure goes up the solubility goes up.
The Solubilities The Solubilities of Several Solids of Several Solids as a Function of as a Function of
TemperatureTemperature
While most substances become more soluble in water with increased Temperature, sodium sulfate and cerium sulfate do not
Pressure Pressure
Changing the pressure doesn’t effect the amount of solid or liquid that dissolves
They are incompressible. However, it does effect gases.
Dissolving GasesDissolving Gases
Pressure effects the amount of gas that can dissolve in a liquid.
The dissolved gas is at equilibrium with the gas above the liquid.
Gases are predictableGases are predictable
As temperature increases, solubility decreases.
Gas molecules can move fast enough to escape.
ConcentrationConcentration A measure of the amount of solute
dissolved in a certain amount of solvent.
Concentrated solution has a large amount of solute.
Dilute solution has a small amount of solute.
Expressed as g/L. But chemical reactions don’t happen in
grams
MolarityMolarity
The number of moles of solute in 1 Liter of the solution.
M = moles/Liter What is the molarity of a solution
with 2.0 moles of NaCl in 4.0 Liters of solution.
.50 mol/L
Making solutionsMaking solutions Pour in a small amount of solvent Then add the solute and dissolve it Then fill to final volume. M x L = moles How many moles of NaCl are
needed to make 6.0 L of a 0.75 M NaCl solution?
4.5 mol