大学化学课件_国外原版教材_4.pptVIP

Aqueous Reactions and Solution Stoichiometry;Ionic Compounds in Water Ions dissociate in water. In solution, each ion is surrounded by water molecules. Transport of ions through solution causes flow of current.;Ionic Compounds in Water;Molecular Compounds in Water Molecular compounds in water (e.g., CH3OH): no ions are formed. If there are no ions in solution, there is nothing to transport electric charge. ;Strong and Weak Electrolytes Strong electrolytes: completely dissociate in solution. For example: Weak electrolytes: produce a small concentration of ions when they dissolve. These ions exist in equilibrium with the unionized substance. For example:;Used to highlight reaction between ions. Molecular equation: all species listed in their molecular forms: HCl(aq) + NaOH(aq) ? H2O(l) + NaCl(aq) Complete ionic equation: lists all ions: H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq) ? H2O(l) + Na+(aq) + Cl-(aq) Net ionic equation: lists only unique ions: H+(aq) + OH-(aq) ? H2O(l) Note that only strong electrolytes are written in ionic form.;Metathesis reactions involve swapping ions in solution: AX + BY ? AY + BX. Metathesis reactions will lead to a change in solution if one of three things occurs: an insoluble solid is formed (precipitate), weak or nonelectrolytes are formed, or an insoluble gas is formed.;Solubility Guidelines for Ionic Compounds;Solubility Guidelines for Ionic Compounds;Acids Dissociation = pre-formed ions in solid move apart in solution. Ionization = neutral substance forms ions in solution. Acid = substances that ionizes to form H+ in solution (e.g. HCl, HNO3, CH3CO2H, lemon, lime, vitamin C). Bases = substances that react with the H+ ions formed by acids (e.g. NH3, Drano?, Milk of Magnesia?).;Strong and Weak Acids and Bases Strong acids and bases are strong electrolytes. They are completely ionized in solution. Weak acids and bases are weak electrolytes. They are partially ionized in solution.;Strong and Weak Acids and Bases Water soluble and ionic = s