chem topic 6 Flashcards
Solutions
mixtures of two or more pure substances
solute
substance present in smaller quantities
solvent
present in larger quantities
dissolution
physical change
-can recover original solute
chemical change- cannot recover original solute
stronger attractions between solute and solvent means
greater solubility
-have to break solute and solvent to make a solution
-2 steps that require energy
process of disolving water
-seperate NaCL and break IMF (V solute)
-separate H2O molecules to make cavity for solute ( V solvent)
-form new IMF interactions between solute and solvent- V mix
V solution= V solute + V solvent + V Mix
V mix must outweigh V solv and V solu
what does miscible mean
can always dissolve no matter how much you put in (sugar)
solubility
maximum amount of solute that can dissolve in a given volume or solvent
saturated solution vs unsaturated vs supersaturated
S: contains maximum amount of dissolved solute
US: contains less than the maximum amount of dissolved solute
SS: more than the maximum amount of solute
common units for solubility
g/100 mL solvent
three factors that affect solubility
solvent-solute interactions- stronger S-S interactions means greater solubility (IMF)
-temp- solubility inc as temp inc
-pressure- sol of gases dec when temp inc
formula for Solubility of gas
Sgas=Kh x P
mass % of solute formula
mass of solute in solution/ total mass of solution x100
Parts per million (ppm)
mass of solute in solution/ total mass of solution x 10x6
Parts per billion (ppb)
mass of solute in solution/ total mass of solution x 10x9
mole fraction
XA= Moles of A/ total moles of all components
-NO UNITS
molarity
Mol of mol/L of solution
-need molar mass
-temperature dependent due to vol changing w temp
molality
-mol of solute/ kg of solvent
-need molar mass
-not temp dependent as mass doesn’t change w temp
Colligative properties and properties present
-number of solute particles present
-vapour pressure
-boiling point
-melting point
vapour pressure
-partial pressure of gas over liquid
-raoult’s law:
-on formula sheet
boiling point elevation and freezing point depression
BP: temp where gas and liquid are eq to atmospheric pressure - presence of solute raises BP
FP: temp where liquid and solid are eq- presence of solute lowers FP
Change in boiling/freezing point
-formula on sheet
-V in T is always positive
-m is molality
-after finding the change, sub for freeze and add for boil to the solvent on back of paper
Compare colligative properties from normal to electrolyte formula
-electrolyte has i in it(van hoffs)
Density
mass/volume
