Chapter 12 Flashcards
solution
A solution is composed of two parts: the solute and the solvent.
solute
The gas (or solid) in a solution of gases (or solids), or the component present in the smaller amount.
solvent
The liquid in the case of a solution of gases or solids, or the component present in the larger amount.
miscible
Fluids that mix with or dissolve in each other in all proportions
immiscible
Fluids that do not dissolve in each other
saturated solution
is in equilibrium with respect to the amount of dissolved solute.
The rate at which the solute leaves the solid state equals
the rate at which the solute returns to the solid state.
solubility
the amount that dissolves in a given quantity of solvent at a given temperature.
unsaturated solution
is a solution not in equilibrium with respect to a given dissolved substance and in which more of the substance can be dissolved.
supersaturated solution
a solution that contains more dissolved substance than a saturated solution does.
when does a supersaturates solution occuer
when a solution is prepared at a higher temperature and is then slowly cooled. This is a very unstable situation, so any disturbance causes precipitation.
Solubility can be understood in terms of two factors:
- The natural tendency toward disorder favors dissolving
2. The relative forces between and within species must be considered.
Stronger forces within solute species _________ dissolving
oppose
Stronger forces between species _____ dissolving.
favor
“Like dissolves like.”
solutes dissolve in solvents that have the same type of intermolecular forces.
The stronger ion-dipole force between the ion and the solvent—that is, hydration energy—________ dissolving.
favors
A stronger force between ions—that is, lattice energy—_______ dissolving.
opposes
The process of dissolving occurs at the
surfaces of the solid
12 | 14In most cases, solubility increases with increasing temperature. However, for a number of compounds, solubility decreases with increasing temperature. Why?
The difference is explained by differences in the heat of solution.
When dissolving absorbs heat (is endothermic), the temperature of the solution _____ as the solute dissolves
decreases
The solubility will ________ as temperature increases (endothermic)
increase
When dissolving releases heat (is exothermic), the temperature of the solution _________ as the solute dissolves
increases
The solubility will ________ as temperature increases (exothermic)
decrease
Henry’s law
describes the effect of pressure on gas solubility
S = kHP