Aqueous solutions Flashcards
Dispersion
process where particles of a substance are scattered throughout another substance. Occurs in covalent compounds where ions not present + do not form in process. Physical change
Solution
homogenous mixture of 2 or more substances
Solvent
Major part of a solution
Solute
Minor part of a solution
Saturated solution
no more solute can be dissolved
Unsaturated solution
More solute can be dissolved into the solute
Physical Change
affects the form of a substance but not its chemical composition
Polarity of water
2 electron pairs in H2O that don’t bond. This side of H2O has much higher electron density than side where H atoms are. This side called delta negative and H side is delta positive. 1 part of water slightly positive charge and other side slightly negative
Dissociation
Ionic compounds separate into their ions. Usually reversible. Occurs in ionic solids where ions are already present before water added. Physical
Hydration
Ions surrounded with water molecules
Ionisation
Molecular substances form ions in solution. Occurs in covalent compounds where ions not present initially but form in solution. Chemical change
Hydrolysis
any chem reaction in which molecule of water breaks 1 or more chem bonds
Chemical Change
Process where 1 substance combines with another form new substance
Electrolyte
Substance that contains free ions and behaves as electrically conductive medium
Factors that affect conductivity of electrolytes
Higher concentration of ions, more conductive. Type of substance that dissolves in water(Strong electrolyte vs weak electrolyte. Strong ones form ions easily weak ones don’t form ions easily). Temperature - higher temp - higher solubility - higher conductivity.
Precipitate
Solid that forms in soln during chem reac
Ion exchange reaction
+ ions exchange their respective - ions due to a driving force
Test for chloride
Add silver nitrate. If white precipitate forms, salt either chloride or carbonate. Then treat precipitate with concentrated nitric acid - if precipitate unchanged = chloride. If effervescence observed salt = carbonate. Carbonate reacts with acid to form CO3
Test for bromides and iodides
Add silver nitrate. AgCl = white, AgBr = cream, AgI = pale yellow. Cl2 + CCl4 added. Cl2 reacts with Br and I ions to form Br2 and I2. Br2 dissolve in CCl4 to form brown layer and if I2 formed it dissolve in CCl4 to form purple layer
Test for sulfate
Add BaCl2. If white precipitate forms, either sulfate or carbonate. Treat with concentrated acid like nitric acid. Sulfates don’t dissolve in acid but carbonates do.
Test for carbonate
Treat with any concentrated acid. If effervescence occurs. If gas bubbled thru limewater and soln becomes milky white, gas is CO2
