Chapter 12-14 Flashcards
Solutions
Homogeneous mixtures of substances composed of solutes and solvents
Solute
A substance that is dissolved (salt)
Solvent
Medium in which a solute is dissolved (ex: water)
Heterogeneous Mixture
Contains undissolved particles large enough to block or scatter light waves (milk)
Homogeneous Mixture
A clear substance, that when a chemical analysis of a sample is done you would find that the proportion of each chemical in the sample remains the same
*uniform mixtures of entities
Electrolytes
Compounds that their aqueous solutions conduct electricity
Non electrolytes
Compounds that their aqueous solutions do not conduct electricity (Determine class of solute based on ohmmeter)
Electrolytes vs nonelectrolytes
Electrolytes are mostly highly soluble ionic compounds and bases (ionic hydroxides)
Nonelectrolytes are molecular compounds
Exception: acids conduct electricity
Dissociation
Describes the separation of ions that occurs when an ionic compound dissolves in water
*water is necessary, but is not consumed nor is a reactant
Ionization
Is the process by which a neutral atom or molecule is converted to an ion
Acids empirical definition
Forms solution that:
- turn blue litmus red
- are electrolytes
- neutralize bases
Acids Arrhenius Theory
Hydrogen compounds to ionize to produce H+ (aq) ions, H+(aq) ions react with OH- (aq) ions to produce water
Bases Empirical Definition
Form solutions that:
- turn red litmus blue
- are electrolytes
- neutralize acids
Bases Arrhenius theory
Ionic hydroxides dissociate to produce OH- (aq) ions, OH- (aq) ions react with H+ (aq) ions to produce water
Neutral Substances empirical definitions
Form solutions that:
- do not affect litmus
- some are electrolytes
- some are non-electrolytes
Neutral Substances Arrhenius theory
No H+ (aq) or OH- (aq) ions are formed, some are ions in solution, some are molecules in solutions
Theoretical Principle of energy
Breaking existing bonds uses energy, forming new bonds release energy
Endothermic
More energy is absorbed than released
Exothermic
More energy is released than absorbed
Strong acids
Acids that are extremely good conductors
Weak acids
Most other common acids
Concentration
Ratio that compares the quantity of solute to the quantity of the solution
Dilute concentration
If it has a relatively small quantity of solute per unit volume of solution
Concentrated solution
Relatively large quantity of solute per unit volume of solution
Concentration Equation
Concentration (c) = quantity of solute/ quantity of solution
Percentage Equation
C= v solute/ v solution x 100%
Percentage by weight volume
C= m solute/ v solution x 100%
Percentage by mass
C= m solute/ m solution x 100%
Parts per million
C= m solute/ m solution x10^6 = M solute (mg) / m solution (kg)
Amount concentration
Chemical amount of solute dissolved in one litre of solution
Amount concentration= chemical amount of solute in moles/ volume of solution (in litres)
Mass, volume and concentration calculations
n=Vc
m=nM
Concentration of Ions
Conductivity suggests the presence of ions in a solution, amount concentrations of the ions in a solution depend on the relative number of ions making up the compound.
Standard solutions
A solution with a concentration that is known with considerable certainty a solution of accurate concentration
Dilution
Quick procedure that begins with a stock solution and to add a solvent (water) to decrease concentration to desired level
Stock solution
Is an initial, concentrated solution from which samples are taken for a dilution
Dilution/ Constant quantity solute Equation
V1C1=VfCf
Concentration is inversely related to solutions Volume
*as volume increases, concentration decreases
Solutions make it easy to
Handle chemicals, complete reactions, control reactions
Saturated solution
A solution in which no more solute will dissolve at a specified temperature (maximum solute concentration)
Dynamic equilibrium is reached
Solubility
Is the concentration of a saturated solution, needs a temperature value
Solids solubility in water
Solids have a higher solubility in water at higher temps
Gases solubility in water
Gases have a higher solubility in water at lower temps, solubility decreases as temp increases. Have a higher solubility in water at higher pressures
Liquids solubility in water
Liquids: polar liquids in water solubility increases the with temp
Immiscible in water
Non polar liquids do not dissolve and form a separate layer
Miscible
Liquids with small polar molecules and hydrogen bonding dissolve completely in any proportion
Elements solubility in water
Have low solubility in water
Solubility table
Of ionic compounds assumes that most substances dissolve in water to some extent, vary from very soluble to slightly soluble, allows to predict state of a compound formed in a reaction in aqueous solution
*cutoff between very and slightly is 0.1 mol/L
In equilibrium
Of solution is in a closed system (no substance can enter or leave), the observable properties become constant
Dynamic equilibrium
The balance that exits when two opposing processes occur at the same rate, solubility Equilibrium must contain both dissolved and undissolved solute at the same time.
Rate at which particles dissolves equals the rate at which particles crystallize
Precipitate
Insoluble product forms a solid
Reaction that forms a solid
Factors that affect solubility
Temperature, pressure, nature of solute and solvent
Supersaturated
A saturated solution may be heated to dissolve extra solute and then carefully cooled to the original temperature without the extra solute crystallizing
Dissolving
When a solute dissolved in a solution, the solid particles move into the solvent to form ions
Crystallization
At the same time, some of the dissolved ions crystallize to Become solid again
Categories of solutions
What their solvent is
If they can conduct electricity
Acidity
