Chemical Reaction Types Adapted from

Predicting Whether a Reaction Will Occur What makes reactants “want” to form products? What makes reactants “want” to form products? Formation of a solid Formation of a solid Formation of water Formation of water Transfer of electrons Transfer of electrons Formation of a gas Formation of a gas

Types of Reactions Synthesis/Combination Decomposition Single Replacement Double Replacement (Precipitation) Combustion Acid/Base (WH) Oxidation-Reduction (Redox)(WH)

Steps to Writing Reactions General steps for writing reactions Identify the type of reaction Predict the product(s) using the type of reaction as a model Balance it Don’t forget about the diatomic elements! (BrINClHOF) For example, Oxygen is O 2 as an element. In a compound, it can’t be a diatomic element because it’s not an element anymore, it’s a compound!

Synthesis/Combination Two substances (generally elements) combine and form a compound reactant + reactant  1 product Basically: A + B  AB Example: 2H 2 + O 2  2H 2 O Example: C + O 2  CO 2

Synthesis Reactions

Learning Check Predict the products. Write and balance the following synthesis reaction equations. Sodium metal reacts with chlorine gas Na (s) + Cl 2(g)  Solid Magnesium reacts with fluorine gas Mg (s) + F 2(g)  Aluminum metal reacts with fluorine gas Al (s) + F 2(g) 

Decomposition Reactions A single compound breaks down into elements or into simpler compounds Often require a catalyst (Heat/light) 1 Reactant  Product + Product In general: AB  A + B Example: 2 H 2 O  2H 2 + O 2 Example: 2 HgO  2Hg + O 2

Decomposition Reactions

Decomposition Exceptions Carbonates and chlorates are special case decomposition reactions that do not go to the elements. Carbonates (CO 3 2- ) decompose to carbon dioxide and a metal oxide Example: CaCO 3  CO 2 + CaO Chlorates (ClO 3 - ) decompose to oxygen gas and a metal chloride Example: 2 Al(ClO 3 ) 3  2 AlCl O 2

Learning Check Predict the products. Then, write and balance the following decomposition reaction equations: Solid Lead (IV) oxide decomposes PbO 2(s)  Aluminum nitride decomposes AlN (s) 

Learning Check Identify each as synthesis or decomposition reactions, and write the balanced equation: N 2(g) + O 2(g)  (nitrogen monoxide) BaCO 3(s)  Co (s) + S (s)  (make Co +3 ) NH 3(g) + H 2 CO 3(aq)  NI 3(s) 

Single Replacement Reactions 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 (-). element + compound  element + compound 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 !!)

Single Replacement Reactions

Activity Series of Metals and Nonmetals Use the Activity Series to predict whether or not a Single Replacement reaction will occur In general, the single metal/halogen must be HIGHER on the list than the metal/halogen in the compound

Activity Series of Metals and Nonmetals Which reaction will occur spontaneously? Which reaction will occur spontaneously? Pb(s)+MgSO 4 (aq)  Mg(s) +PbSO 4 (aq) Pb(s)+MgSO 4 (aq)  Mg(s) +PbSO 4 (aq) Mg(s)+PbSO 4 (aq)  Pb(s)+MgSO 4 (aq) Mg(s)+PbSO 4 (aq)  Pb(s)+MgSO 4 (aq)

Learning Check Decide whether the following single replacement reactions will occur. If so, predict the products and balance the equation Zn (s) + HCl (aq)  NaCl (s) + F 2(g)  Al (s) + Cu(NO 3 ) 2(aq)  Ca (s) + KNO 3(aq)  KBr (aq) + I 2(s) 

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 Compound + compound  compound+ compound 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 Example: AgNO 3(aq) + NaCl (s)  AgCl (s) + NaNO 3(aq) Another example: K 2 SO 4(aq) + Ba(NO 3 ) 2(aq)  KNO 3(aq) + BaSO 4(s) 2

Solubility Rules Use the solubility rules chart to predict whether a reaction will occur Use the solubility rules chart to predict whether a reaction will occur A formation of one precipitate (solid) indicates a reaction A formation of one precipitate (solid) indicates a reaction If two soluble (aqueous) compounds form, then there is no visible reaction If two soluble (aqueous) compounds form, then there is no visible reaction Most of the rules are written in terms of anions, so look at the anion first! Most of the rules are written in terms of anions, so look at the anion first!

Solubility Rules Rule #If the compound contains…Aqueous or Solid? 1 Any Group 1A cation (H +, Li + Na +, K + ) Ammonium (NH 4 + ) Always aqueous 2 Acetate (C 2 H 3 O 2 - ) Chlorate (ClO 3 - ) Nitrate (NO 3 - ) Always aqueous 3 Sulfate (SO 4 -2 )Aqueous UNLESS paired with Pb +2, Hg +2, Ag +, Ba +2, Sr +2, or Ca +2 4 Halides (F -, Cl -, Br -, I - ) Aqueous UNLESS paired with Pb +2, Hg +2, Ag + 5 Carbonate (CO 3 -2 ) Phosphate (PO 4 -3 ) Chromate (CrO 4 -2 ) Sulfide (S -2 ) Hydroxide (OH - ) Solid UNLESS paired with any cation from Rule #1

Learning Check Predict if the following compounds will be Aqueous or Solid Predict if the following compounds will be Aqueous or Solid CaCO 3 CaCO 3 NaCl NaCl PbSO 4 PbSO 4 BaCl 2 BaCl 2 KNO 3 KNO 3 AgPO 4 AgPO 4 MgC 2 H 3 O 2 MgC 2 H 3 O 2 FeS FeS

Learning Check 1. Decide if the following reactions will produce a solid precipitate. 2. Predict the products and balance the equations a. HCl (aq) + AgNO 3(aq)  b. CaCl 2(aq) + Na 3 PO 4(aq)  c. Pb(NO 3 ) 2(aq) + BaCl 2(aq)  d. FeCl 3(aq) + NaOH (aq)  e. H 2 SO 4(aq) + NaOH (aq)  f. KOH (aq) + CuSO 4(aq) 

5. Combustion Reactions (Burning) Combustion reactions occur when a hydrocarbon (C x H y ) reacts with oxygen gas Carbon Dioxide, Water and Heat are produced The “Fire Triangle” 1) A Fuel (hydrocarbon) 2) Oxygen 3) Ignition Source (spark)

Combustion Reactions In general: C x H y + O 2  CO 2 + H 2 O Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C 8 H 18 ) Incomplete burning can also result in the production of carbon monoxide (CO) oRngPHRj0vA

Learning Check Example C 5 H 12 + O 2  CO 2 + H 2 O Write the products and balance the following combustion reactions: C 10 H 22 + O 2  CH 4 + O 2  5 6 8

Learning Check - Mixed Practice State the type, predict the products, and balance the following reactions: BaCl 2 + H 2 SO 4  C 6 H 12 + O 2  Zn + CuSO 4  Cs + Br 2  FeCO 3 

Acid/Base Reactions (WH) Acid – substance that donates H + ions Acid – substance that donates H + ions HCl+H 2 O  H 3 O + (aq) +Cl - (aq) HCl+H 2 O  H 3 O + (aq) +Cl - (aq) hydronium ion hydronium ion Base – substance that accepts H + ions Base – substance that accepts H + ions NH 3 +H 2 O  NH 4 + (aq) +OH - (aq) NH 3 +H 2 O  NH 4 + (aq) +OH - (aq) hydroxide ion hydroxide ion Strengths of acids and bases are determined by how much H + they can donate or accept in solution Strengths of acids and bases are determined by how much H + they can donate or accept in solution We will only focus on strong acids and bases in this chapter We will only focus on strong acids and bases in this chapter

Acid/Base Reactions (WH) A strong acid and a strong base will react to form water and a salt (ionic compound) A strong acid and a strong base will react to form water and a salt (ionic compound) HCl (aq) +NaOH (aq)  H 2 O+NaCl (aq) HCl (aq) +NaOH (aq)  H 2 O+NaCl (aq)

Learning Check (WH) Write out the following acid/base reactions Write out the following acid/base reactions 1. Aqueous nitric acid reacts with aqueous potassium hydroxide 2. Aqueous sulfuric acid reacts with aqueous calcium hydroxide

Oxidation-Reduction Reactions (WH) Any reaction that involves a transfer of electrons Any reaction that involves a transfer of electrons Metal reacts with Non-metal (ionic compound) Metal reacts with Non-metal (ionic compound) 2Na (s) +Cl 2(g)  2NaCl (s) 2Na (s) +Cl 2(g)  2NaCl (s) Two non-metals react (O 2 reactant/product) Two non-metals react (O 2 reactant/product) CH 4(g) +2O 2(g)  CO 2(g) +2H 2 O (g) CH 4(g) +2O 2(g)  CO 2(g) +2H 2 O (g)

Learning Check (WH) For each of the following reactions, show how electrons are gained and lost For each of the following reactions, show how electrons are gained and lost 2Al (s) +3I 2(s)  2AlI 3(s) 2Al (s) +3I 2(s)  2AlI 3(s) 2Cs(s)+F 2(g)  2CsF (s) 2Cs(s)+F 2(g)  2CsF (s)

Exothermic and Endothermic Reactions Reactions will either absorb or release energy as they progress Reactions will either absorb or release energy as they progress Exothermic Reactions Exothermic Reactions release energy (heat is a product) release energy (heat is a product) Temperature of system increases Temperature of system increases Endothermic Reactions Endothermic Reactions absorb energy (heat is a reactant) absorb energy (heat is a reactant) Temperature of system decreases Temperature of system decreases

Exothermic and Endothermic Reactions Exothermic – Combustion Reaction Exothermic – Combustion Reaction CH 4 +O 2  CO 2 +H 2 O+ heat CH 4 +O 2  CO 2 +H 2 O+ heat Heat is written as a product Heat is written as a product Endothermic –Baking Soda and Vinegar Reaction Endothermic –Baking Soda and Vinegar Reaction NaHCO 3 + HC 2 H 3 O 2 +heat  NaHCO 3 + HC 2 H 3 O 2 +heat  CO 2 +H 2 O+NaC 2 H 3 O 2 Heat is written as a reactant Heat is written as a reactant

Reactions in Aqueous Solution (WH) Molecular equations – overall reactions Molecular equations – overall reactions Full Ionic Equation – represents all AQUEOUS reactants ad products as ions Full Ionic Equation – represents all AQUEOUS reactants ad products as ions Any aqueous compound is split into ions Any aqueous compound is split into ions Any solid, liquid or gas is unchanged Any solid, liquid or gas is unchanged Net Ionic Equation – includes only those components that undergo a change Net Ionic Equation – includes only those components that undergo a change Spectator ions – ions that do not participate in the reaction Spectator ions – ions that do not participate in the reaction Spectator ions remain as ions on both sides of the equation and are eliminated Spectator ions remain as ions on both sides of the equation and are eliminated

Molecular Equation: K 2 CrO 4 + Pb(NO 3 ) 2  PbCrO KNO 3 AqueousAqueousSolid Aqueous Full Ionic Equation: 2 K + + CrO Pb NO 3 -  PbCrO 4 (s) + 2 K NO 3 - Full Ionic Equations (WH)

Net Ionic Equations (WH) Using the Full ionic equations, cancel out ions that appear on BOTH sides of the equation Using the Full ionic equations, cancel out ions that appear on BOTH sides of the equation Total Ionic Equation: 2 K + + CrO Pb NO 3 -  PbCrO 4 (s) + 2 K NO 3 - Net Ionic Equation: CrO Pb +2  PbCrO 4 (s)

Learning Check (WH) Write the molecular, full ionic and net ionic equations for the following reactions Write the molecular, full ionic and net ionic equations for the following reactions Silver nitrate reacts with Lead (II) Chloride in hot water. Silver nitrate reacts with Lead (II) Chloride in hot water. Aqueous sodium sulfide is mixed with aqueous copper (II) nitrate. Aqueous sodium sulfide is mixed with aqueous copper (II) nitrate. Zinc metal reacts with hydrochloric acid. Zinc metal reacts with hydrochloric acid.