7Review of ConceptsThe diagrams here show three compounds AB2 (a), AC2 (b), and AD2 (c) dissolved in water. Which is the strongest electrolyte and which is the weakest? (For simplicity, water molecules are not shown.)
15General Properties Acid base Sour taste Color changes in plant dyes React with metals to produce H2 gasReact with carbonates and bicarbonates to produce CO2 gasAqueous acid solutions conduct electricityTaste bitterFeel slipperyColor changes in plant dyesAqueous base solutions conduct electricity
16Brønsted Acid and Bases Proton donorMonoproticDiproticTriproticProton acceptor
17Strong acids Strong bases HIHBrHClO4HClH2SO4HNO3NaOHKOHLiOHRbOHCsOH Ca(OH)2Ba(OH)2Sr(OH)2Strong acids/bases are strong electrolytes and will completely dissociate in water.
18Review of ConceptsWhich of the following diagrams best represents a weak acid? Very weak acid? Strong acid? The proton exists in water as the hydronium ion. All acids are monoprotic. (For simplicity, water molecules are not shown.)
19Acid-Base Neutralization Reaction between an acid and a baseGenerally aqueous solutions result in water and a saltEx: HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l)*this is a strong acid and strong base so they completely dissociate and the net ionic equation isH+(aq) + OH−(aq) H2O(l)Ex: HCN(aq) + NaOH(aq) NaCN(aq) + H2O(l)*this is a weak acid and strong base so the acid does not completely ionize in water. When writing the ionic and net ionic equations you cannot break the weak acid apart! The net ionic equation isHCN(aq) + OH−(aq) CN−(aq) + H2O(l)
20Gas formationCertain salts react with acids to produce gaseous productsHNO3 breaks down into H2O(l) + NO2(g) + NO(g)H2CO3 breaks down into H2O(l) + CO2(g)H2SO3 breaks down into H2O(l) + SO2(g)NH4OH breaks down into H2O(l) + NH3(g)H2S(g)CO2(g)H2(g)If you get one of these as a product in your molecular equation, they immediately breakdown as aboveGasses do not ionize
21Double Replacement Rxns Review Driving ForceHow do you recognize it?PrecipitateYou must memorize the solubility rules. Any compound formed from two ions can be recognized as soluble (written as separate ions) or as a precipitate (written as a molecule).Gas formedYou must memorize the combinations that decompose into gases (there are 4). You must also memorize the gases that form. For example, when you H2SO3 as a product, you must know it decomposes into H2O and SO2 gas.Weak electrolyteYou must memorize the short list of strong acids and strong bases so you will recognize all the weak acids and bases that dissolve, but do not dissociate into ions. The weak base ammonia, NH3, is in this category. It exits in water as NH3(aq) and only slightly forms the ions NH4+ + OH−
23Half-reaction OIL RIG Oxidation reaction Reduction reaction Reaction that involves the loss of electronsContains reducing agent-donates electronsInvolves the gain of electronsContains oxidizing agent-accepts electrons
24Oxidation NumberCharge of the atom would have in a molecule if electrons were transferred completelyRulesUncombined elements = 0Neutral compounds sum = 0Ion = ion charge (polyatomic ions sum to charge)ExceptionsHydrogen +1 w/ nonmetals, −1 w/ metalsOxygen −2 except w/ fluorine (+2), in peroxides (−1)Fluorine ALWAYS −1
38ExampleA g sample of an ionic compound containing chloride ions and an unknown metal is dissolved in water and treated with and excess of AgNO3. if g of AgCl precipitate forms, what is the percent by mass of Cl in the original compound?
43ExampleA mL volume of M KMnO4 solution is needed to oxidize mL of a FeSO4 solution in an acidic medium. What is the concentration of the FeSO4 solution in molarity? The net ionic equation is 5Fe2+ + MnO4− + 8H+ Mn2+ + 5Fe3+ + 4H2O