Solubility, Solutions, IMFs, and Colligative Properties Flashcards
What occurs during dissociation?
An ionic compound separates into anions and cations when placed in water.
Provide an example of dissociation.
Na_2S (aq) –> 2Na^+ (aq) + S^2- (aq)
K_2SO_4(aq) –> 2K^+(aq) + SO_4 ^2- (aq)
What occurs during ionization?
A compound dissolves into ions when placed in water.
What makes a compound miscible?
When a molecular compound dissolves into molecules (NOT ions) when placed in water.
Provide an example of a miscible substance.
Sugar.
Sugar (s) + Water (l) –> Sugar water(aq)
What must occur to form strong electrolytes?
A chemical substance completely ionizes into its ions.
Can conduct electricity.
Provide examples of strong electrolytes.
Soluble salts, Strong acids, and Strong bases.
HCl(aq) –> H^+ + Cl^-.
What must occur to form weak electrolytes?
A chemical substance partially ionizes into its ions.
Can conduct electricity, but not as well as strong electrolytes.
Provide examples of weak electrolytes.
Weak acids and weak bases.
CH_3COOH (aq) <—-> CH_3COO^- (aq) + H^+ (aq)
What occurs to form non-electrolytes?
A chemical substance that dissolves in water but not as ions.
Cannot conduct electricity.
Provide examples of non-electrolytes.
Polar substances (ex: sugar and alcohol).
C_6 H_12 O_6 (s) –> C_6 H_12 O_6 (aq)
What makes a compound soluble?
If it dissolves in the given solvent.
What makes a compound insoluble?
If it does NOT dissolve in the given solvent.
What three factors affect solubility?
- Temp. Direct.
- Volume. Direct.
- Pressure (Gas solubility).
True or False: All gases are soluble in one another.
True.
What three ions, if present, make a compound soluble?
- Li^+
- Na^+
- K^+
No exceptions.
What three polyatomic ions, if present, makes a compound soluble?
- C_2 H_3 O_2^-
- NO_3^-
- NH_4^+
What are the solubility exceptions for substances containing Cl^-, I^-, and Br^-?
- Ag^+
- Pb^2+
- Hg_2^2+
What are the solubility exceptions for substances containing SO_4^2-?
- Ag^+
- Pb^2+
- Ca^2+
- Sr^2+
- Ba^2+
What are the insolubility exceptions for substances containing OH^-?
- Li^+
- NH_4^+
- Na^+
- K^+
- All Group 1 metals.
What are the insolubility exceptions for substances containing CO3^2- and PO_4^3-?
- Li^+
- NH_4^+
- Na^+
- K^+
What are the insolubility exceptions for substances containing S^2-?
- Li^+
- NH_4^+
- Na^+
- K^+
- Ca^2+
- Sr^2+
- Ba^2+
What occurs during decomposition?
The reactant decomposes into two or more products.
A –> B+C
What occurs during synthesis?
Two or more reactants combine to make a product(s).
A+B –> C+D
What are the four types of synthesis reactions?
- Double displacement/precipitation.
- Single displacement.
- Reduction-Oxidation (Redox).
- Neutralization.
What occurs during neutralization?
An equal acid is mixed with an equal base.
A type of double displacement.
What occurs during double displacement/precipitation?
Two reactants are mixed, resulting in the formation of a solid in/on the product side.
What occurs during a redox reaction?
There is a transfer of electrons, resulting in ions being formed.
What is a common type of redox reaction?
Combustion reactions.
A substance is burned in the presence of oxygen, resulting in water and carbon dioxide being created.
*Corrosion is another type of redox reaction.
What occurs during a single displacement reaction?
Gases are formed.
What occurs on the reactants side of a double displacement reaction?
The reactants switch IONS to create the products.
AD + BC –> AC + BD
*Remember to balance the charges of the products.
During the ion exchange during double displacement, which ion moves- the anion or the cation?
The anion is switched out and the cation is fixed in place.
After charge balancing in a double displacement reaction, what must be checked next?
Solubility.
If soluble, mark it as aqueous (aq).
If insoluble, mark it as solid (s).
What happens if both products in a double displacement reaction are aqueous?
No reaction occurs.
What are precipitation reactions?
A reaction that occurs between aqueous solutions of ionic compounds results in an insoluble ionic compound called a precipitate.
*Solubility rules apply.
What are the three types of equations?
- Complete Molecular Equation
- “Complete Ionic Equation”
- “Net Ionic Equation”
What step must be taken to create a complete ionic equation?
The soluble molecules are separated into their ions, and the insoluble species are kept together.
What does the net ionic equation show?
It shows only the species actually participating in the reaction.
All other ions are called spectator ions.
What are intermolecular forces?
The forces that bind atoms together within chemical or molecule bonds.
What are intramolecular forces?
The attractive forces that exist between molecules and atoms.
Which is stronger: intermolecular or intramolecular forces?
Intramolecular forces.
*However, intermolecular forces are strong enough to influence physical properties (ex: viscosity).
What are the types of intermolecular forces?
- Ion-dipole.
- Dipole-dipole.
- Hydrogen bonding.
- Dipole-induced (Van der Waals, London forces, Dispersion).
What are the types of intramolecular forces?
- Molecular.
- Ionic.
- Covalent (non-polar/true and polar).
How are dispersion/ Van der Waals/ London forces created?
Temporary fluctuations in the electron distribution in atoms or molecules create a temporary dipole.
What type of force do all molecules possess?
dispersion/ London/ Van der Waals.
What is the strength of dispersion forces based on?
The number of contact points the molecules have with one another. The more, the better.
How are dipole-dipole forces created?
When polar molecules have a permanent dipole. The more polar, the stronger the dipole-dipole force.
What is the relationship between molecule size and boiling point?
Direct.
What is the relationship between atomic radius and boiling point?
Direct.
What type of force is a hydrogen bond a specific version of?
Dipole-Dipole.
How are hydrogen bonds created?
When a hydrogen atom bonds with an F, O, or N atom.
Why is hydrogen bonding necessary for life on Earth?
It holds together DNA and water.
How are ion dipoles formed?
When ions from an ionic compound are attracted to the dipole of a polar molecule in a mixture.
What does the strength of the ion-dipole determine?
The solubility of the ionic compound in its solvent.
What is the order of intermolecular forces from weakest to strongest?
- Dispersion/London/Van der Waals.
- Dipole-Dipole.
- Hydrogen bonding.
- Ion-dipole.
What does solubility depend on?
The attractive forces between the solute molecules and the solvent molecules.
True or False: Unlike polarities dissolve with each other.
False. Like dissolves like.
What happens when a polar compound mixes with a non-polar compound?
They do not react and they end up layering (ex: oil and water).
What occurs when the solute-to-solvent attraction is weaker than the sum of the solute-to-solute and solvent-to-solvent attractions?
The solution will not form unless the energy difference is small enough to be overcome by the increase in entropy from mixing.
What is molarity?
A unit of concentration that can be prefixed.
(mols solute/L solution).
What is molality?
The mols of solute per 1 kg. of solvent. Value does not vary with temperature.
(mols solute/Kg solvent).
What is mole fraction?
Moles of solute over total moles of solution. Unitless.
(mols solute/mols solution).
What is mole percent?
Mole fraction x 100%.
What are percent by mass concentrations?
Amount of solute per amount of solution multiplied by 100.
Weight of solute + weight of solvent= Weight of solution.
((Weight of solute/ weight of solution) x 100%).
What is parts per million (ppm) by weight?
(solute weight/ solution weight) x 10^6). Can be used with volumes.
If both the solute and solvent in a two-component Raoult’s Law system are volatile, what does the delta P look like?
Delta P (solution) = xsolute x P^0 solvent.
* Both are liquid.
What is lowering the vapor pressure in a two-component system equivalent to?
The solute’s mole fraction.
What equation is used to give the vapor pressure of a volatile solvent over a solution?
P(solvent) = x(solvent) x P^0 (solvent).
What equation is used to give the vapor pressure of a volatile solute over a solution?
P(solute) = x(solute) x P^0 (solute).
What kinds of compounds produce multiple solute particles from a single formula unit?
Ionic.
What is the van’t Hoff factor or i?
The ratio of moles of solute particles to moles of formula units dissolved.
How does a solution’s freezing point compare to a pure solvent’s?
It is lower or depressed.
How does a solution’s boiling point compare to a pure solvent’s?
It is higher or elevated.
What is osmotic pressure?
The force that counterbalances the pressure of the solvent molecules moving through a semipermeable membrane.
Produced by extra solution.
What is the osmotic pressure equation?
pi = iMRT.
What is the driving force of osmosis and most energy?
Entropy.
