Types of Reactions

precipitate: a solid product that forms in an aqueous solution reaction Na2CO3 + Ca(NO3)2 (aq) CaCO3 + (s) 2 NaNO3 (aq) (aq) “chunks” “sinkies” “floaties” ppt clear Na2CO3 solution clear Ca(NO3)2 solution cloudy solution containing CaCO3(s) and NaNO3(aq)

Key Terms Term Definition In an Equation soluble able to be dissolved (aq)  insoluble does not dissolve in solution (or water)  (ins) precipitate an insoluble solid formed when two solutions are mixed (s) 

Using Solubility Rules Most solubility rules are written based on the negative ion or anion

How to Determine if a Compound is Soluble or Insoluble? Find the anion in the compound. Find the rule in the solubility tables that matches the ion. Double check to make sure the cation isn’t listed as an exception.

Predict if the following compounds are soluble or insoluble. CaCl2 CuSO4 Al2(CrO4)3 Mg(OH)2 AgCl SrS Soluble Insoluble Insoluble Insoluble Soluble

Predicting if a Precipitate will Form Precipitate reactions are precipitation reactions. In order for a reaction to be a precipitation reaction, there must be one solid product, which is the precipitate, and both reactants should be aqueous solutions

Determine which reactions are precipitation reactions or reactions that will form a precipitate. Pb(NO3)2 + KI  PbI2 + KNO3   (NH4)2CO3 + K2S  K2CO3 + (NH4)2S Ag + Cu(NO3)2  AgNO3 + Cu Ba(OH)2 + Fe(ClO4)3  Ba(ClO4)2 + Fe(OH)3 (aq) (aq) (s) (aq) YES NO (aq) (aq) (aq) (aq) NO (s) (s) (aq) (aq) YES (aq) (aq) (aq) (s)

Neutralization Reaction A reaction between and acid and a base which results in the production of a salt and water. ACID + BASE = SALT + WATER HCl(aq) + NaOH(aq) = H2O(l) + NaCl(aq) Mg(OH)2(s) + 2HCl(aq) = MgCl2(aq) + 2H2O(l)

Reduction-Oxidation Reaction REDOX A reaction in which electrons are transferred from one species to another. Oxidation means the loss of electrons. Reduction means the gain of electrons. LEO says GER Loss Electrons = Oxidation Gain Electrons = Reduction Many oxidation-reduction reactions are single replacement reactions

Oxidation Reduction Reactions (Redox) Each sodium atom loses one electron: Each chlorine atom gains one electron:

Lose Electrons = Oxidation LEO says GER : Lose Electrons = Oxidation Sodium is oxidized Gain Electrons = Reduction Chlorine is reduced

Rules for Assigning Oxidation Numbers Rules 1 & 2 The oxidation number of any uncombined element is zero 2. The oxidation number of a monatomic ion equals its charge

Rules for Assigning Oxidation Numbers Rules 3 & 4 3. The oxidation number of oxygen in compounds is -2 4. The oxidation number of hydrogen in compounds is +1

Rules for Assigning Oxidation Number Rule 5 5. The sum of the oxidation numbers in the formula of a compound is 0 2(+1) + (-2) = 0 H O (+2) + 2(-2) + 2(+1) = 0 Ca O H

Rules for Assigning Oxidation Numbers Rule 6 6. The sum of the oxidation numbers in the formula of a polyatomic ion is equal to its charge X + 4(-2) = -2 S O X + 3(-2) = -1 N O  X = +5  X = +6

Assigning Oxidation States Example: Assign oxidation states to all atoms in the following. CO2  O = SF6  F = NO3-  O = MnO4-  O = HSO3-  O = H2O  H = Li3N  Li = -2 (for each oxygen); C = +4 -1 (for each fluorine); S = +6 -2 (each oxygen); N = +5 -2 (each oxygen); Mn = +7 -2 (each oxygen); H = +1, S = +4 +1 (each); O = -2 +1 (each); N = -3