University:
Winston-Salem Forsyth County Schools
Course:
AP Chemistry
Academic year:

2014
Views:

312

Pages:

3
Author:

ophantseu884

AQUEOUS REACTIONS ● A solution is a homogeneous mixture of two or more substances. ● All aqueous solutions can be classified in terms their ability to conduct electricity. ● If a substance forms ions in solution, it is an electrolyte and will conduct electricity. Ie. NaCl ● If a substance does not form ions in solution, it is a nonelectrolyte and does not conduct electricity.Ie. sugar ● Compounds whose aqueous solutions conduct electricity well are strong electrolytes. Compounds whose solutions conduct electricity poorly are weak electrolytes. ● Exchange (metathesis) reactions involve the exchange of ions in solution. ● Ionic equations: 2KI(aq)+Pb(NO3)2(aq)→PbI2(s)+2KNO3(aq) ● Both potassium iodide and lead nitrate are colorless solutions. When mixed they form lead iodide, a yellow precipitate. ● The molecular equation lists all species in their molecular form ● The complete ionic equation lists all strong soluble electrolytes as ions:Pb2+(aq)+2NO3-(aq)+2K+(aq)+2I-(aq)→PbI2(s)+2K+(a q)+2NO3-(aq) ● The net ionic equation lists only those ions not common on both sides of the reaction:Pb2+(aq)+2I-(aq)→PbI2(s) ● The spectator ions that are present in the solution , but play no direct role in the reaction are eliminated in the net equation. ● Acids are substances that ionize in aqueous solutions to form H+. Acids are proton donors. Bases are proton acceptors. Bases react with the H+ to form water. ● Strong acids and bases are strong electrolytes. They ionize completely in solution. ● Strong bases include Group1A metal hydroxides, Ca(OH)2, Ba(OH)2, and Sr(OH)2 ● Strong acids include HCl, HBr, HI, HClO3, H2SO4, and HNO3 ● Weak acids and weak bases are weak electrolytes. They partially ionize in solution. ● A neutralization reaction occurs when an acid and base react. The result is the formation of a salt and water ● Acids react with carbonates and hydrogen carbonates to form carbon dioxide and water ● H+(aq)+ HCO3-(aq)→H2O(l)+CO2(g) ● Reaction of sulfides with acid generate hydrogen sulfide ● 2H+(aq)+S2+(aq)→H2S(g) ● When a substance loses electrons, it undergoes oxidation(OIL): Ca(s)+2H+(aq)→Ca2+(aq)+H2(g). ● When a substance gains electrons, it undergoes reduction(RIG): 2Ca(s)+O2(g)→2CaO(s) ● The reaction of a metal with an acid or a metal salt is called a displacement reaction: A+BX→AX+B ● It is common for metals to produce hydrogen gas when they react with acids. ● Mg(s)+2HCl→MgCl2(aq)+H2(g) molecular ● Mg(s)+2H+→Mg2+(aq)+ H2(g) net ionic ● The metal is oxidized and the H+is reduced. ● It is possible for metals to be oxidized in the presence of a salt:Fe(s)+Ni(NO3)2(aq)→Fe(NO3)2(aq)+Ni(s) molecular ● Fe(s)+ Ni2+(aq)→Fe2+(aq)+Ni(s) net ionic ● In this case, iron is oxidized and nickel is reduced. ● If one substance is oxidized, another substance must be reduced. ● Molarity=moles of solute/liters of solution ● When an ionic compound dissolves, the relative concentration of ions depends on the chemical formula ● For 1M NaCl, the solution is 1M in Na+ ; 1M in Cl● For 1M Na2SO4, the solution is 2M in Na+; 1M in SO4● When making dilutions, MinitialVinitial=MfinalVfinal