NOTES: CHEMICAL REACTIONS

1 1 CHAPTER 11 NOTES: CHEMICAL REACTIONS VOCABULARY: Products what is formed in a CHEMICAL reaction; right of arrow Reactants what goes into a CHEMICAL reaction; left of arrow yields + and (s) solid (l) liquid (g) gas (aq) aqueous only works when dissolved in water Catalyst a substance that speeds up a reaction but is not itself consumed; provides an easier reaction pathway that requires less activation energy Activation Energy (Ea) energy necessary to initiate a CHEMICAL reaction heat Pt ENERGY OF CHEMICAL REACTIONS : Exothermic Reaction: H is Endothermic Reaction: H = + (heat is a product ) (heat is a reactant ) Energy Time Energy Time 2 BALANCED CHEMICAL REACTIONS Law of Conservation of Matter: matter cannot be created or destroyed in a CHEMICAL reaction WORD FORMULA BALANCED equations 1. word equation: Hydrogen gas reacts with oxygen gas to form water formula equation: ____ H2 + O2 H2O _____ diagram: H H + O = O O + O H H H H H H balanced reaction ____2 H2 + O2 2 H2O _____ 2.

2 Word equation: Magnesium reacts with hydrochloric acid solution (HCl in water) to form magnesium chloride and hydrogen. Formula equation: ____ Mg + HCl MgCl2 + H2 _____ diagram: Mg + H Cl Cl-1Mg+2Cl-1 + H H H Cl balanced reaction _____ Mg + 2 HCl MgCl2 + H2 _____ 3 Try balancing these CHEMICAL REACTIONS : a. 2 Na + H2SO4 Na2SO4 + H2 b. 2 K + Cl2 2 KCl c. S8 + 8 O2 8 SO2 d. 3 F2 + 2 FeBr3 2 FeF3 + 3 Br2 e. 3 H2SO4 + 2 Al Al2(SO4)3 + 3 H2 f. 2 NaNO3 + Ca(MnO4)2 2 NaMnO4 + Ca(NO3)2 g.

3 C4H8 + 6 O2 4 CO2 + 4 H2O h. 2 C2H6 + 7 O2 4 CO2 + 6 H2O 4 Balancing CHEMICAL equations Balance the equations below: 1) ____ N2 + ____ H2 ____ NH3 2) ____ KClO3 ____ KCl + ____ O2 3) ____ NaCl + ____ F2 ____ NaF + ____ Cl2 4) ____ H2 + ____ O2 ____ H2O 5) ____ Pb(OH)2 + ____ HCl ____ H2O + ____ PbCl2 6) ____ AlBr3 + ____ K2SO4 ____ KBr + ____ Al2(SO4)3 7) ____ CH4 + ____ O2 ____ CO2 + ____ H2O 8) ____ C3H8 + ____ O2 ____ CO2 + ____ H2O 9) ____ C8H18 + ____ O2 ____ CO2 + ____ H2O 10) ____ FeCl3 + ____ NaOH ____ Fe(OH)3 + ____NaCl 11) ____ P + ____O2 ____P2O5 12) ____ Na + ____ H2O ____ NaOH + ____H2 13) ____ Ag2O ____ Ag + ____O2 14) ____ S8 + ____O2 ____ SO3 15) ____ CO2 + ____ H2O ____ C6H12O6 + ____O2 16) ____ K + ____ MgBr ____ KBr + ____ Mg 17) ____ HCl + ____ CaCO3 ____ CaCl2 + ____H2O + ____ CO2 18) ____ HNO3 + ____ NaHCO3 ____ NaNO3 + ____ H2O + ____ CO2 19) ____ H2O + ____ O2 ____ H2O2 20) ____ NaBr + ____ CaF2 ____ NaF + ____ CaBr2 ANSWERS.

4 1) 1 + 3 2 2) 2 2 + 3 3) 2 + 1 2 + 1 4) 2 + 1 2 5) 1 + 2 2 + 1 6) 2 + 3 6 + 1 7) 1 + 2 1 + 2 8) 1 + 5 3 + 4 9) 2 + 25 16 + 18 10) 1 + 3 1 + 3 11) 4 + 5 2 12) 2 + 2 2 + 1 13) 2 4 + 1 14) 1 + 12 8 15) 6 + 6 1 + 6 16) 2 + 1 2 + 1 17) 2 + 1 1 + 1 + 1 18) 1 + 1 1 + 1 + 1 19) 2 + 1 2 20) 2 + 1 2 + 1 5 SYNTHESIS, DECOMPOSITION AND COMBUSTION REACTIONS Types of REACTIONS : Synthesis (Combination), Decomposition and Combustion Synthesis (Combination) A + B AB (1 product only) Decomposition AB A + B (1 reactant only) Combustion of a hydrocarbon CxHy + O2 CO2 + H2O Practice: Balance each reaction below. Then identify the reaction type. a. H2 + Br2 2 HBr __synthesis_____ b. C4H8 + 6 O2 4 CO2 + 4 H2O __combustion_____ c. 2 NaOH Na2O + H2O __decomposition_____ d.

5 Ba(ClO3)2 BaCl2 + 3 O2 __decomposition_____ 6 First write and balance the equation. Then identify the reaction type. e. phosphorus + oxygen tetraphosphorus decoxide __ synthesis _____ 4 P + 5 O2 P4O10 f. pentane (C5H12) + oxygen carbon dioxide + water __ combustion _____ C5H12 + 8 O2 5 CO2 + 6 H2O g. magnesium chlorate magnesium chloride + oxygen ___ decomposition _____ Mg(ClO3)2 MgCl2 + 3 O2 h. when solid calcium carbonate is heated calcium oxide and carbon dioxide are formed ___ decomposition _____ CaCO3 CaO + CO2 i. the formation of calcium nitride from calcium and nitrogen ___ synthesis _____ 3 Ca + N2 Ca3N2 j. sulfur trioxide mixes with water in the atmosphere to form sulfuric acid ___ synthesis _____ SO3 + H2O H2SO4 7 NOTES: SINGLE REPLACEMENT REACTIONS & DOUBLE REPLACEMENT REACTIONS 1.

6 Single Displacement REACTIONS (aqueous ONLY) metals: standard: A(s) + BX (aq) AX (aq) + B(s) example: Cu + 2 AgNO3 Cu(NO3)2 + 2 Ag metal + acid: standard: A(s) + HX (aq) AX (aq) + H2(g) example: Mg + 2 HCl MgCl2 + H2 metal + water: standard: A(s) + H2O(l) AOH(aq) + H2(g) example: 2 K + 2 H2O 2 KOH + H2 halogens: standard: X2 + AY AX + Y2 example: F2 + 2 KI 2 KF + I2 2. Double Displacement (aqueous only) standard : AX (aq) + BY (aq) AY(aq) + BX(s) example : Ba(NO3)2 + NaI BaI2 + NaNO3 3. Identify the reaction type for each reaction below. Then complete and balance the reaction. _single displacement_ a. Ba + 2 AgNO3 Ba(NO3)2 + 2 Ag __single displacement_____b. F2 + 2 KI 2 KF + I2 __double displacement c.

7 NaOH + CaCl2 2 NaCl + Ca(OH)2 ___single displacement d. Zn + H2SO4 ZnSO4 + H2 8 WRITING WORD equations __decomposition_____1. aluminum chlorate aluminum chloride + oxygen 2 Al(ClO3)3 9 O2 + 2 AlCl3 __SR_____ 2. lithium + iron (III) nitrate lithium nitrate + iron 3 Li + Fe(NO3)3 3 LiNO3 + Fe __decomposition_____ 3. magnesium carbonate magnesium oxide + carbon dioxide MgCO3 MgO + CO2 __synthesis_____ 4. tin + nitrogen tin (IV) nitride 3 Sn + 2 N2 Sn3N4 __SR_____ 5. Zinc reacts with nitric acid to form zinc nitrate and hydrogen Zn + 2 HNO3 Zn(NO3)2 + H2 __decomposition_____6. calcium hydroxide breaks down to form calcium oxide and water Ca(OH)2 CaO + H2O WRITING WORD equations WITH PREDICTING PRODUCTS __synthesis_____ 1. aluminum + oxygen 4 Al + 3 O2 2 Al2O3 __SR_____ 2. sodium + silver nitrate Na + AgNO3 NaNO3 + Ag __SR_____ 3.

8 Magnesium + hydrochloric acid Mg + 2 HCl MgCl2 + H2 ___DR_____ 4. solutions of iron (III) nitrate + potassium sulfate are mixed 2 Fe(NO3)3 + 3 K2SO4 Fe2(SO4)3 + 6 KNO3 ____SR_____ 5. Chlorine gas is bubbled through a solution of lithium iodide Cl2 + 2 LiI 2 LiCl + I29 PREDICTING PRODUCTS 1) ____ Ag2SO4 + __2__ NaNO3 2 AgNO3 + Na2SO4 2) __2__ NaI + ____ CaSO4 CaI2 + Na2SO4 3) __2__ HNO3 + ____ Ca(OH)2 2 H2O + Ca(NO3)2 4) ____ Zn + ___2__ HNO3 Zn(NO3)2 + H2 5) ____ AlCl3 + ____ (NH4)3PO4 AlPO4 + 3 NH4Cl 6) ___3_ Pb + ___2_ Fe(NO3)3 3 Pb(NO3)2 + 2 Fe 7) ___2_ C3H6 + __9__ O2 6 CO2 + 6 H2O 8) ____ Ca + ____ Na2SO4 CaSO4 + 2 Na 10 PREDICTING PRODUCTS FOR THREE TYPES OF DECOMPOSITION REACTIONS : Try: a. strontium carbonate _____strontium oxide + carbon dioxide_____ ____SrCO3 SrO + CO2_____ b.

9 Aluminum carbonate _____aluminum oxide + carbon dioxide_____ ____Al2(CO3)3 Al2O3 + 3 CO2_____ Try: a. calcium hydroxide _____calcium oxide + water_____ _____Ca(OH)2 CaO + H2O_____ b. Iron(III) hydroxide _____iron (III) oxide + water_____ _____2 Fe(OH)3 Fe2O3 + 3 H2O_____ 1. metal carbonate metal oxide + carbon dioxide example: sodium carbonate sodium oxide + carbon dioxide Na2CO3 Na2O + CO2 2. metal hydroxide metal oxide + water example: sodium hydroxide sodium oxide + water 2 NaOH Na2O + H2O 11 Try: a. barium chlorate _____barium chloride + oxygen_____ _____Ba(ClO3)2 BaCl2 + 3 O2_____ b. lithium chlorate _____lithium chloride + oxygen_____ _____2 LiClO3 2 LiCl + 3 O2_____ 3. metal chlorate metal chloride + oxygen example: sodium chlorate sodium chloride + oxygen 2 NaClO3 2 NaCl + 3 O2 12 KINETICS: RATE OF CHEMICAL REACTIONS Collision Theory: for a reaction to occur, the reactants must collide with sufficient energy and with the proper orientation (and in the correct ratio) Factors Affecting Reaction Rate: 1.

10 Temperature if temperature is increased, the reaction will be quicker. faster moving particles collide more often, and more particles will have enough energy (Ea) when they collide 2. Particle size (surface area) more exposed particles causes more collisions, so there will be more collisions with the correct orientation 3. Concentration Number of particles in a given volume affects rate of concentration more particles, more collisions 4. Adding a Catalyst or Inhibitor a catalyst speeds up a reaction by lowering the required activation energy an inhibitor slows down a reaction by raising the activation energy 13 WRITING WORD equations a. lithium + nitrogen lithium nitride 6 Li + N2 2 Li3N b. aluminum + oxygen aluminum oxide 4 Al + 3 O2 2 Al2O3 c. sodium carbonate sodium oxide + carbon dioxide Na2CO3 Na2O + CO2 d. zinc + phosphoric acid zinc phosphate + hydrogen gas 3 Zn + 2 H3PO4 Zn3(PO4)2 + 3 H2 e.