unit 6 Flashcards
solution
homogeneous mixture of 2 substances
solvent
majority component of a solution
aqueous solution
a solution where water acts as a solvent
solute
minority component of a mixture
dilute solution
small amount of solute dissolved in the solvent
concentrated solution
large amount of solute dissolved in the solvent
saturated solution
a solution in which the solution is in equilibrium with the undissolved state
unsaturated solution
has less than the maximum amount of solute dissolved in the solvent
supersaturated solution
more than the maximum amount of solute is dissolved
can be obtained by preparing a saturated solution at a high temperature, then cooled carefully to avoid crystallizing the excess solute
metastable
in a saturated solution, excess solute will crystallize if the solution is shaken or if a seed crystal is added to start crystallization
concentration
expression of solute : solvent in a solution and is often expressed as amount of solute per volume of solution
molarity
the number of moles of solute per liter of solution
molar concentration conversion factors
1.5 mol x = 1 L x soln
1.5 mol x / 1 L x soln
1 L x soln / 1.5 mol x
ratios are just for example*
standard solution
solution of a known concentration
stock solution
solutions stored in concentrated forms
formula used in dilution problems
m1v1 = m2v2
m1: concentration of stock solution
v1: volume of stock solution
m2: concentration of desired solution
v2: volume of desired solution
entropy
measure of energy randomization or dispersal in a system
how does entropy work?
-gases have kinetic energy due to particle motion
-when barrier is removed, each gas and its kinetic energy is dispersed
-the gas mixture has a greater energy dispersal than the separated components
steps of dissolving
- energy is used to break attractions between solvent particles
- energy is used to break attractions between solute particles
- energy is released when new attractions are formed between solvent and solute particles, energy is used as heat
-when the energy released is less than the energy used, the shortfall is compensated by the increased entropy of the solution
entropy strength when dissolved: solids
greatest increase
entropy strength when dissolved: liquids
moderate increase
entropy strength when dissolved: gases
no increase
lattice energy
energy needed to disrupt the crystal
-very strong
-lattice breaking should not occur
why do strong electrolyte solutions conduct electricity strongly?
-ionic substances dissociate completely into ions when dissolved in water
-some molecular compounds ionize when dissolved in water
ionization
molecule breaks apart into ions
why do weak electrolyte solutions conduct electricity weakly?
-other compounds dissociate/ionize less than 10%
-most common are weak acids and weak bases
why do nonelectrolyte solutions not conduct electricity?
molecular compounds are soluble in water, but form no compounds