How do chemists know what to mix together to make the products they want??? Substances react with one another in similar ways depending on their chemical makeup and driving forces of different situations.

Combination (or Synthesis) when two or more substances react to form one product A + Z  AZ

Types: Synthesis Example C + O 2 OO C +  OO C OO C OO C O O C O O C O O C O O C O O C O O C O O C O O C O O C O O C O O C O O C General: A + B  AB

Practice: determine how the following substances combine to form a new more complex compound and then BALANCE Mg(s) + O 2 (g)  ??? Na(s) + Cl 2 (g)  ??? Zn (s) + S (s)  ??? Zn (s) + I 2 (s)  ???

Decomposition RxNs When a complex compound undergoes a reaction and breaks apart to produce two or more other (more simpler) substances –(heat or light may be used to do this) AZ  A + Z

Types: Decomposition Example: NaCl General: AB  A + B  Cl Na Cl + Na

Types: Decomposition Example 2HgO  O Hg O OO + General: AB  A + B

Decomposition of Metal Hydrogen Carbonate Compounds When a metal hydrogen carbonate, upon heating, will breaks down to yield a metal carbonate compound, water and carbon dioxide 2NaHCO 3 (s)  Na 2 CO 3 (s) + H 2 O (g) + CO 2 (g) The delta (triangle) in the equation means that heat is applied

Decomposition of Metal Carbonate Compounds When a metal carbonate, after prolonged heating, breaks down to yield a metal oxide compound and carbon dioxide CaCO 3 (s)  CaO (s) + CO 2 (g)

Decomposition of Chlorate Compounds A chlorate will break down to yield its binary salt and oxygen gas. KClO 3 (s)  KCl (s) + O 2 (g)

Practice: determine how each complex compound will break down into simpler substances and then BALANCE NO 2  ??? CaCO 3  ??? KHCO 3  ??? H 2 O  ???

Combustion Rapid reaction that produces a flame Involves O 2 from the air as a reactant C 3 H 8 (g) + O 2 (g)  CO 2 (g) + H 2 O (g) –C 3 H 8 is common propane from your gas grill –This is the complete combustion of propane Hydrocarbons are compounds that contain ONLY carbon and hydrogen Complete combustion of hydrocarbons in oxygen produces ONLY water and carbon dioxide

Practice: determine the products of these complete combustion reactions and then BALANCE C 6 H 12 + O 2  ??? CH 4 + O 2  ??? C 4 H 8 + O 2  ???

Single Displacement RxNs When one more reactive metal (as per the activity series) displaces another less active metal (or hydrogen) from a compound or solution A(s) + BZ  AZ + B(s)

Types: Single displacement Example: Zn + CuCl 2  Zn Cl Cu + General: AB + C  AC + B Cl Zn Cu +

Activity Series Foiled again – Aluminum loses to Copper Element Reactivity Li K Ba Sr Ca Na Mg Al Mn Zn Cr Fe Co Ni Sn Pb H 2 Cu Ag Hg Pt Au Halogen Reactivity F 2 Cl 2 Br 2 I 2 More Active Less Active

How to determine if a single replacement reaction will occur… when Mg (s) + CoSO 4 (aq) ? 1) Find both metals (Mg & Co) on activity series 2) If lone metal (Mg) is higher up on activity series than the metal in the compound (Co)…Mg is more reactive thus it will take Co’s position and replace it in the compound 3) If Mg is not more reactive…then No Reaction occurs… –HERE…Mg is higher up on the activity series so it is more reactive than Co …THUS the reaction WILL occur Mg(s) + CoSO 4 (aq)  MgSO 4 (aq) + Co(s)

Types of Reactions

Practice (determine if a reaction will occur, if a reaction occurs then predict the products and balance if necessary)) Zn(s) + HBr (aq)  Mg(s) + H 2 O (l)  Cd(s) + HNO 3 (aq)  Al (s) + H 2 SO 4 (aq) 

3. Single Replacement Reactions Single Replacement Reactions occur when one element replaces another in a compound. Single Replacement Reactions occur when one element replaces another in a compound. A metal can replace a metal (+) OR a nonmetal can replace a nonmetal (-). A metal can replace a metal (+) OR a nonmetal can replace a nonmetal (-). element + compound  product + product element + compound  product + product A + BC  AC + B (if A is a metal) OR A + BC  BA + C (if A is a nonmetal) (remember the cation always goes first!) When H 2 O splits into ions, it splits into H + and OH - (not H+ and O -2 !!)

4. Double Replacement Reactions Double Replacement Reactions occur when a metal replaces a metal in a compound and a nonmetal replaces a nonmetal in a compound Double Replacement Reactions occur when a metal replaces a metal in a compound and a nonmetal replaces a nonmetal in a compound Compound + compound  product + product Compound + compound  product + product AB + CD  AD + CB AB + CD  AD + CB

Double Replacement Reactions Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together Example: Example: AgNO 3(aq) + NaCl (s)  AgCl (s) + NaNO 3(aq) AgNO 3(aq) + NaCl (s)  AgCl (s) + NaNO 3(aq) Another example: Another example: K 2 SO 4(aq) + Ba(NO 3 ) 2(aq)  KNO 3(aq) + BaSO 4(s) 2

Practice Predict the products. Balance the equation Predict the products. Balance the equation 1. HCl (aq) + AgNO 3(aq)  2. CaCl 2(aq) + Na 3 PO 4(aq)  3. Pb(NO 3 ) 2(aq) + BaCl 2(aq)  4. FeCl 3(aq) + NaOH (aq)  5. H 2 SO 4(aq) + NaOH (aq)  6. KOH (aq) + CuSO 4(aq) 

Will a compound dissolve in water? A compound that DOES dissolve in water its called soluble A compound that DOES NOT dissolve in water its called insoluble 1) Write the formula of the following compounds 2) Predict if each compound will dissolve in water Sodium chloride Barium acetate Potassium sulfate Calcium phosphate 3) Use your solubility guidelines to check to see if you “guessed” correctly ((find the anion on the left side of the table and determine if it IS or IS NOT soluble…then check the exceptions to each on the right side of the table))

Precipitation (exchange or metathesis) When two soluble compounds exchange ions (replace OR displace one another) in order to form at least one insoluble product (this is insoluble and falls out of solution as a precipitate) AX + BZ  AZ + BX either AZ or BX MUST be a precipitate  if no precipitate forms then no reaction occurs

Will a precipitate form? Use Your Solubility Guidelines: 1) Note the individual ions present 2) Consider how each ion could “switch partners” to form new combinations 3) Use the guidelines to determine ((find the anion on the left side of the table and determined if it is OR is not soluble…then check the exceptions to each on the right side of the table)) if the new combinations of “switched partners” are insoluble (do not dissolve in water) 4) The insoluble possibility will force the reaction to occur by forming a precipitate and falling out of solution

Will a precipitate form… when solutions of Mg(NO 3 ) 2 and NaOH are mixed? All are aqueous so you have ions Mg +2 & NO 3 - ; Na + & OH - Possible interacts are Mg +2  OH - and Na +  NO 3 - Checking solubility guidelines…most hydroxides (OH’s) are insoluble and Mg(OH) 2 is NOT an exception the reaction occurs as Mg(NO 3 ) 2 (aq) + 2NaOH (aq)  Mg(OH) 2 (s) + 2NaNO 3 (aq)

Practice: determine if a reaction occurs; if yes, then predict the products and balance the equation MgSO 4 (aq) + BaCl 2 (aq)  ??? AlBr3(aq) + Na 2 Cl 2 (aq)  ??? AgC 2 H3O 2 (aq) + SrI 2 (aq)  ??? FeSO 4 (aq) + Ca(OH) 2 (aq)  ???

Ionic Equations Shows ions completely dissolved in water (strong electrolytes) as ions in the chemical equation Mg(NO 3 ) 2 (aq) + 2NaOH (aq)  Mg(OH) 2 (s) + 2NaNO 3 (aq) Equation showing chemical formulas only is called molecular equation Mg +2 (aq) + 2(NO 3 ) - (aq) + 2Na + (aq) + 2 OH - (aq)  Mg(OH) 2 (s) + 2Na + (aq) + 2NO 3 - (aq) Equation showing ALL IONS PRESENT (as ions) is called complete ionic equation Mg +2 (aq) + 2 OH - (aq)  Mg(OH) 2 (s) Equation showing ONLY IONS THAT TAKE PART IN REACTION (as ions) is called NET ionic equation Ions that do not take part in reaction (appear in identical forms on both sides) are called spectator ions If every ion in a complete ionic equation is a spectator, then NO reaction occurs!!!

Practice Write the complete ionic reaction for AgC 2 H3O 2 (aq) + SrI 2 (aq)  ??? AND THEN Write the corresponding net ionic reaction

Practice Write the complete ionic reaction for FeSO 4 (aq) + Ca(OH) 2 (aq)  ??? AND THEN Write the corresponding net ionic reaction