Chapter 13 - Properties of Solutions
Solutions - Homogeneous mixtures of two or more pure substances.
Solute - Part being dissolved. Usually smaller in quantity.
Solvent - Thing that dissolves.
Solvation - Dissolving process.
Hydration - The dissolving process with water as the solvent.
Substances depend on these to form solutions.
Intermolecular forces
Natural tendency to mix.
Mixing of gases is spontaneous.
Mixing causes more randomness in the position of molecules increasing the entropy.
Solute-solute interactions - Must be overcome to disperse these particles when making a solution.
Solvent-solvent interactions - Must be overcome to make room for the solute.
Solvent-solute interactions - Occur as the particles mix.
ΔH solvent - Energy required to vaporize.
Solubility - How much solute can be dissolved in a given amount of solvent at a given temperature.
Saturated solutions - Can’t add more solute. More than enough.
Unsaturated solutions - Can add more. Not enough.
Supersaturated solutions - Temporary situation where the solution is cooled slowly and for it to react, a crystal from the solute is added.
Solute-solvent interactions
Temperature
As it goes up, more solute is dissolved
Pressure (for gas solutes)
As it goes up, more solute can be added.
Solubility of solids and liquids isn’t affected by pressure.
Gas solubility is affected by pressure
Henry’s Law - The solubility of a gas is proportional to the partial pressure of the gas above the solution. It’s only true at a constant temperature.
For most solids, as temperature increases, solubility increases.
For all gases, as temperature increases, solubility decreases.
Mass percentage (% m/m)
Parts per million (ppm)
Parts per billion (ppb)
Mole fraction (X)
Molarity (M)
Molality (m)
They depend only on the quantity, not on the identity of the solute.
Vapor pressure reduction
Boiling point elevation
Freezing point depression
Osmotic pressure
Raoult’s Law
i - Van-Hoff factor, the number of ions you get when dissolving the compound.
Kb is a constant different for all compounds.
Kf is a constant different for all compounds.
Osmosis - The net movement of solvent molecules from a solution of low to a high concentration of solute across a semipermeable membrane.
Semipermeable membrane - Smaller particles pass through it, but it blocks larger particles.
Osmotic pressure - The applied pressure to stop bigger particles.
If two solutions separated by a semipermeable membrane have the same osmotic pressure, no osmosis occurs.
Colloids - Suspension of particles larger than individual ions or molecules, but too small to be settled out by gravity.
Ex. → Blood
They have a hydrophobic end (tail) and a hydrophilic end (head).
Solutions - Homogeneous mixtures of two or more pure substances.
Solute - Part being dissolved. Usually smaller in quantity.
Solvent - Thing that dissolves.
Solvation - Dissolving process.
Hydration - The dissolving process with water as the solvent.
Substances depend on these to form solutions.
Intermolecular forces
Natural tendency to mix.
Mixing of gases is spontaneous.
Mixing causes more randomness in the position of molecules increasing the entropy.
Solute-solute interactions - Must be overcome to disperse these particles when making a solution.
Solvent-solvent interactions - Must be overcome to make room for the solute.
Solvent-solute interactions - Occur as the particles mix.
ΔH solvent - Energy required to vaporize.
Solubility - How much solute can be dissolved in a given amount of solvent at a given temperature.
Saturated solutions - Can’t add more solute. More than enough.
Unsaturated solutions - Can add more. Not enough.
Supersaturated solutions - Temporary situation where the solution is cooled slowly and for it to react, a crystal from the solute is added.
Solute-solvent interactions
Temperature
As it goes up, more solute is dissolved
Pressure (for gas solutes)
As it goes up, more solute can be added.
Solubility of solids and liquids isn’t affected by pressure.
Gas solubility is affected by pressure
Henry’s Law - The solubility of a gas is proportional to the partial pressure of the gas above the solution. It’s only true at a constant temperature.
For most solids, as temperature increases, solubility increases.
For all gases, as temperature increases, solubility decreases.
Mass percentage (% m/m)
Parts per million (ppm)
Parts per billion (ppb)
Mole fraction (X)
Molarity (M)
Molality (m)
They depend only on the quantity, not on the identity of the solute.
Vapor pressure reduction
Boiling point elevation
Freezing point depression
Osmotic pressure
Raoult’s Law
i - Van-Hoff factor, the number of ions you get when dissolving the compound.
Kb is a constant different for all compounds.
Kf is a constant different for all compounds.
Osmosis - The net movement of solvent molecules from a solution of low to a high concentration of solute across a semipermeable membrane.
Semipermeable membrane - Smaller particles pass through it, but it blocks larger particles.
Osmotic pressure - The applied pressure to stop bigger particles.
If two solutions separated by a semipermeable membrane have the same osmotic pressure, no osmosis occurs.
Colloids - Suspension of particles larger than individual ions or molecules, but too small to be settled out by gravity.
Ex. → Blood
They have a hydrophobic end (tail) and a hydrophilic end (head).
