Chemical Equations & Reactions Chemical Reaction - Study Questions 1. What is a chemical reaction? 2. What is evidence a reaction has occurred? 3. What is a chemical equation? 4. Define reactants. 5. Define products. 6. Define catalyst. 7. What information is found in an equation? 8. What symbols are used to represent the states of matter? 9. What is the meaning of “aq”? 10. How do you indicate a catalyst is being used in a reaction? 11. What is activation energy? 12. What the three things does conservation of matter require of chemical equations? 13. What is the procedure for balancing a chemical equation? 14. Balance the equation for the reaction of magnesium chloride and silver nitrate to form magnesium nitrate and silver chloride. 15. What is a synthesis reaction? 16. How is a combustion reaction related to a synthesis reaction? 17. What type of reaction is an explosion? 18. Compare decomposition and dissociation. 19. What determines whether one metal will replace another in a single displacement reaction? 20. What is the general form of a double displacement reaction? 21. What type of reaction is each of these? 2Na(s) + Cl2(g)  2NaCl(s) PCl5(s)  PCl3(s) + Cl2(g) 2Al(s) + Fe2O3(s)  2Fe(s) + Al2O3(s) C6H12O6(s) + 6O2(g)  6CO2(g) + 6H2O(l) BaCl2(aq) + H2SO4(aq)  2HCl(aq) + BaSO4(s) 22. What is the oxidation number of an element? 23. What is the oxidation number of the fluorine ion? 24. What is the sum of the oxidation numbers in a compound? 31. Can a redox reaction form a molecule? Explain your answer. http://www.unit5.org/chemistry/Equations.html

Lecture Outline – Chemical Equations & Reactions student notes outline textbook questions Lecture Outline – Chemical Equations & Reactions textbook questions Keys text http://www.unit5.org/chemistry/Equations.html

Chemical Reactions You should be able to Classify reactions by type. Write a balanced molecular equation, complete ionic equation, and a net ionic equation. Balance oxidation-reduction reactions. Predict if a precipitate will form using the solubility rules. Predict products of reactions given the chemical names of the reactants. What you should learn: In chemical change atoms are rearranged but no atoms are created and none are destroyed Chemical equations are symbolic representations of what is happening at the molecular level and are used to communicate the conditions under which a reaction proceeds, the products and amount of energy that results, and allow for predictions to be made. More Specifically...: Classify those equations that come under the heading of synthesis, decomposition, single replacement, double replacement, neutralization, oxidation/ reduction and combustion Identify and name acids and bases Use principle of conservation of mass to balance a reaction From a written description of a reaction write a balanced reaction using correct state symbols Show that the conservation of mass is true for a balanced reaction Predict the products of chemical reactions (including state symbols) when given the reactants. Use an activity series to predict the spontaneity of reactions. Use solubility rules to predict the formation of a precipitate Define oxidation and reduction, and identify any species undergoing oxidation or reduction, and identify the oxidizing and reducing agents Write half reactions for single replacement reactions (monoatomic ions only) Fast Track to a 5 (page 61) To know how to calculate the molecular mass of a covalent compound and the formula mass of an ionic compound To be able to use the concepts of the mole and molar mass to calculate the number of atoms, molecules, or formula units in a sample of a substance To be able to determine the empirical formula of a compound from its composition by mass To know how to derive the molecular formula of a compound from its empirical formula To be able to describe a chemical reaction To know how to calculate the quantities of compounds produced or consumed in a chemical reaction To identify fundamental types of chemical reactions To begin to predict the types of chemical reactions that substances undergo

Organize Your Thoughts Chemical reactions Chemical equations Chemical equations To identify the reactants and products in a chemical equation. To balance a chemical equation with coefficients. To identify synthesis (combination), decomposition, and combustion reactions. To identify single-replacement reactions. To identify double-replacement reactions. To predict the products of a reaction. Synthesis Decomposition Single replacement Double replacement Combustion Balancing equations Predicting products from reactants Packard, Jacobs, Marshall, Chemistry Pearson AGS Globe, page 175

Describing a Chemical Reaction Indications of a Chemical Reaction Evolution of heat, light, and/or sound Production of a gas Formation of a precipitate Color change Objective: To state four observations that are evidence for a chemical reaction. Photo of precipitate: http://www.geocities.com/chem_reactions/Images/Precipitate.jpg

Signs of Chemical Reactions There are five main signs that indicate a chemical reaction has taken place: release input change in color change in odor production of new gases or vapor input or release of energy difficult to reverse

Chemical Equations Depict the kind of reactants and products aluminum oxide Depict the kind of reactants and products and their relative amounts in a reaction. reactants product 4 Al(s) + 3 O2(g) 2 Al2O3(s) A chemical equation is an expression that gives the identities and quantities of the substances in a chemical reaction Chemical formulas and other symbols are used to indicate the starting material(s) or reactant(s), which are written on the left side of the equation, and the final compound(s) or product(s), which are written on the right side. An arrow, read as yields or reacts to form, points from the reactants to the products. Abbreviations are added in parentheses as subscripts to indicate the physical state of each species:—(s) for solid, (l) for liquid, (g) for gas, and (aq) for an aqueous solution. A balanced chemical equation is when both the numbers of each type of atom and the total charge are the same on both sides. A chemical reaction represents a change in the distribution of atoms but not in the number of atoms. http://img.alibaba.com/photo/10784694/Aluminum_Oxide_Abrasive_Fine_Grit_120_220_.jpg http://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Corundum_Aluminum_Oxide_Gallantin_Co_MontanaDSC03201.jpg/600px-Corundum_Aluminum_Oxide_Gallantin_Co_MontanaDSC03201.jpg http://www.germes-online.com/direct/dbimage/50327532/Aluminum_Alloy_Pipe.jpg The letters (s), (g), and (l) are the physical states of compounds. The numbers in the front are called stoichiometric coefficients.

Chemical Equations 4 Al(s) + 3 O2(g) 2 Al2O3(s) aluminum oxide sandpaper 4 Al(s) + 3 O2(g) 2 Al2O3(s) 4 g Al + 3 g O2 yield 2 g Al2O3 This equation means: 4 Al atoms + 3 O2 molecules yield 2 molecules of Al2O3 or 4 Al moles + 3 O2 moles yield 2 moles of Al2O3 4 mol Al@27g/mol 3 mol O2@32g/mol 2 mol Al2O3@102g/mol 108 g + 96 g = 204 g

Chemical Equations Because the same atoms are present in a reaction at the beginning (reactants) and at the end (products), the amount of matter in a system does not change. The Law of Conservation of Matter Law of Conservation of Matter means that nothing is “lost” or “stolen”. In the real world retail theft costs business lots (much of the theft is actually employee theft)! 20% 100% Chemical Factory 100% 80% Kotz web

Chemical Equations Because of the principle of the conservation of matter, An equation must be balanced. It must have the same number of atoms of the same kind on both sides. Lavoisier, 1788

Characteristics of Chemical Equations The equation must represent known facts. The equation must contain the correct formulas for the reactants and products. The law of conservation of mass must be satisfied.

Chemical Equations Reactants – the substances that exist before a chemical change (or reaction) takes place. Products – the new substance(s) that are formed during the chemical changes. CHEMICAL EQUATION indicates the reactants and products of a reaction. Objectives: To identify seven elements that occur naturally as diatomic molecules, H2, N2, O2, F2, Cl2, Br2, I2. [HOBrFINCL twins or BrINClHOF brothers] To write a chemical equation from the description of a chemical reaction. REACTANTS  PRODUCTS

Word Equations A WORD EQUATION describes chemical change using the names of the reactants and products. Write the word equation for the reaction of methane gas with oxygen gas to form carbon dioxide and water. methane + oxygen carbon dioxide + water Reactant Product CH4 + 2 O2 CO2 + 2 H2O

Unbalanced and Balanced Equations H Cl Cl H Cl Cl H H H2 + Cl2  HCl (unbalanced) H2 + Cl2  2 HCl (balanced) reactants products H Cl reactants products H Cl 2 1 2 2 2 1 2 2

Visualizing a Chemical Reaction 2 Na + Cl2 NaCl 2 ___ mole Na 10 10 ___ mole Cl2 5 5 ___ mole NaCl 10 10 ?

Visualizing a Chemical Reaction 2 Na + Cl2 NaCl 2

Meaning of Chemical Formula Symbol Meaning Composition H2O One molecule of water: Two H atoms and one O atom 2 H2O Two molecules of water: Four H atoms and two O atoms H2O2 One molecule of hydrogen peroxide: Two H atoms and two O atoms

Balancing Chemical Equations Balanced Equation – one in which the number of atoms of each element as a reactant is equal to the number of atoms of that element as a product What is the relationship between conservation of mass and the fact that a balanced equation will always have the same number of atoms of each element on both sides of an equation? Objective: To write balanced chemical equations by inspection. Balanced chemical equation – Provides qualitative information about the identities and physical states of the reactants and products – Provides quantitative information because it tells the relative amounts of reactants and products consumed or produced in the reaction – The number of atoms, molecules, or formula units of a reactant or product in a balanced chemical equation is the coefficient of that species – Mole ratio of two substances in a chemical reaction is the ratio of their coefficients in the balanced chemical equation Determine whether the following equation is balanced. 2 Na + H2O  2 NaOH + H2 2 Na + 2 H2O  2 NaOH + H2

Balancing Chemical Equations Write a word equation for the reaction. Write the correct formulas for all reactants and products. Determine the coefficients that make the equation balance.

Balancing Chemical Equations Other examples NO(g) + O2(g)  NO2(g) is it balanced? Is this balanced? NO(g) + O(g)  NO2(g) Is this OK? Is this balanced? NO(g) + ½ O2(g)  NO2(g) Is this OK?

Balancing Chemical Equations An important point to remember 2 NO(g) + O2(g)  2NO2(g) The 2 to the left of NO(g) and NO2(g) refers to the number of molecules present in the balanced equation. It is a “multiplier” for every atom in the molecule. http://images.google.com/imgres?imgurl=http://www.uwec.edu/Images/UWECWeb/uwec8.gif&imgrefurl=http://www.uwec.edu/carneymj/Chem103.htm&h=67&w=359&sz=10&hl=en&start=101&tbnid=7T7IE0FudtwTnM:&tbnh=23&tbnw=121&prev=/images%3Fq%3Dgeneral%2Bchemistry%2Bpowerpoint%26start%3D90%26gbv%3D2%26ndsp%3D18%26hl%3Den%26sa%3DN The subscript 2 in O2 (g) and NO2(g) refers to the number of atoms of this type that are present in each molecules (or ionic compound).

Guidelines for Balancing Chemical Equations 1) polyatomic ions first ? 2) even / odd (make all even) 3) H2O Mg(OH)2 2 H-OH vs. 4) single elements last Example: need 13 oxygen atoms 13 2 “ ” Multiply by O2 = 13 Method for balancing chemical equations 1. Identify the most complex substance. 2. Beginning with that substance, choose an element that appears in only one reactant and one product. Adjust the coefficients to obtain the same number of atoms of this element on both sides. 3. Balance polyatomic ions (if present) as a unit. 4. Balance the remaining atoms, usually ending with the least- complex substance and using fractional coefficients if necessary. If a fractional coefficient is used, multiply both sides of the equation by the denominator to obtain whole numbers for the coefficients. 5. Count the numbers of atoms of each kind on both sides of the equation to be sure that the chemical equation is balanced. 13 2 3X + O2 2Y + Z 3X + O2 2Y + Z 13 2 2 6X + 13 O2 4Y + 2Z

(NH4)3PO4 + Mg(OH)2  Mg3(PO4)2 3 + 6 NH4OH ? 2 (NH4)3PO4 + Mg(OH)2  Mg3(PO4)2 3 + 6 NH4OH ammonium phosphate magnesium hydroxide magnesium phosphate ammonium hydroxide NH41+ OH1- Now you try… 2 AlCl3 + Li2CO3  Al2(CO3)3 + LiCl 3 6

Balancing Chemical Equations           Balancing Equations (visual)           Balancing Chemical Equations           www.funbasedlearning.com Keys (visual) http://www.unit5.org/chemistry/Equations.html

Write a balanced equation for the reaction between chlorine and sodium bromide to produce bromine and sodium chloride. 1) Write a word equation for the reaction. chlorine + sodium bromide  bromine + sodium chloride 2) Write the correct formulas for all reactants and products. Cl2 + NaBr  Br2 + NaCl 3) Determine the coefficients that make the equation balance. Cl2 + 2 NaBr  Br2 + 2 NaCl

Write the balanced equation for the reaction between aluminum sulfate and calcium chloride to form a white precipitate of calcium sulfate. 1) Write a word equation for the reaction. ? ? aluminum sulfate + calcium chloride  calcium sulfate + aluminum chloride 2) Write the correct formulas for all reactants and products. Al2(SO4)3 + CaCl2  CaSO4 + AlCl3 3) Determine the coefficients that make the equation balance. Al2(SO4)3 + 3 CaCl2  3 CaSO4 + 2 AlCl3

CH4 + 2 O2  CO2 + 2 H2O Reactants Products 1 C atom 1 C atom 4 H atoms 4 H atoms 4 O atoms 4 O atoms

Reactants  Products + C(s) + O2(g) CO2(g) + H2(g) + O2(g) H2O (l) 2 2 carbon oxygen carbon dioxide Reactants Product 1 carbon atom 1 carbon atom 2 oxygen atoms 2 oxygen atoms catalyst – speeds up reaction + Pt H2(g) + O2(g) H2O (l) hydrogen oxygen water 2 Pt 2 Reactants Product 4 hydrogen atoms 4 hydrogen atoms 2 oxygen atoms 2 oxygen atoms Reactants Product 2 hydrogen atoms 2 hydrogen atoms 2 oxygen atoms 1 oxygen atoms Reactants Product 2 hydrogen atoms 4 hydrogen atoms 2 oxygen atoms 2 oxygen atoms Un balanced

Reactants  Products catalyst – speeds up reaction 2 2 Unbalanced

Showing Phases in Chemical Equations H2O(s) H2O(l) H2O(g) Solid Phase – the substance is relatively rigid and has a definite volume and shape. NaCl(s) Liquid Phase – the substance has a definite volume, but is able to change shape by flowing. H2O(l) Gaseous Phase – the substance has no definite volume or shape, and it shows little response to gravity. Cl2(g)

Additional Symbols Used in Chemical Equations “Yields”; indicates result of reaction Used to indicate a reversible reaction A reactant or product in the solid state; also used to indicate a precipitate Alternative to (s), but used only to indicate a precipitate A reactant or product in the liquid state A reactant or product in an aqueous solution (dissolved in water) A reactant or product in the gaseous state (s) (l) (aq) (g)

Additional Symbols Used in Chemical Equations Alternative to (g), but used only to indicate a gaseous product Reactants are heated Pressure at which reaction is carried out, in this case 2 atm Pressure at which reaction is carried out exceeds normal atmospheric pressure Temperature at which reaction is carried out, in this case 0 oC Formula of catalyst, in this case manganese (IV) oxide, used to alter the rate of the reaction D 2 atm pressure 0 oC MnO2

Solubility Ionic Equations Cover the answers, work the problem, then check the answer. 1. Dissolve ammonium nitrate: 2. Precipitate cupric hydroxide: 3. Dissolve chromium thiocyanate: 4. Precipitate lead arsenate: 5. Dissolve silicon permanganate: 6. Precipitate zinc phosphate: NH4NO3 (s) ---> NH4+1 (aq) + NO3-1 (aq) Cu+2 (aq) + 2OH-1 (aq) ---> Cu(OH)2 (s) Cr(SCN)3 (s) ---> Cr+3 (aq) + 3SCN-1 (aq) 3Pb+2 (aq) + 2AsO4-3 (aq) ---> Pb3(AsO4)2 (s) Si(MnO4)4 (s) ---> Si+4 (aq) + 4MnO4-1 (aq) 3Zn+2 (aq) + 2PO4-3 (aq) ---> Zn3(PO4)2 (s)

Types of Chemical Reactions Synthesis (Combination) reaction A + B  AB Decomposition reaction AB  A + B ASingle-replacement reaction A + BC  AC + B element compound compound element BDouble-replacement reaction AB + CD  AD + CB compound compound compound compound Neutralization reaction HX + BOH  BX + HOH Objective: To classify a chemical reaction as one of the following types: combination (synthesis), decomposition, single replacement, double replacement, or neutralization. acid base salt water CH + O2  CO2 + H2O Combustion reaction (of a hydrocarbon) Polymerization Polymer = monomer + monomer + … Ause activity series to predict Bdriving force…water, gas, or precipitate

Types of Chemical Reactions Synthesis (Combination) reaction A + B  AB Decomposition reaction AB  A + B ASingle-replacement reaction A + BC  AC + B BDouble-replacement reaction AB + CD  AD + CB Neutralization reaction HX + BOH  BX + HOH CH + O2  CO2 + H2O Objective: To classify a chemical reaction as one of the following types: combination (synthesis), decomposition, single replacement, double replacement, or neutralization. Combustion reaction (of a hydrocarbon) Polymerization Polymer = monomer + monomer + … Ause activity series to predict Bdriving force…water, gas, or precipitate

Nitrogen is in excess – or hydrogen is limiting reagent. Chemical Equations Chemical Equations N2 (g) + 3 H2 (g) 2 NH3 (g) + “Microscopic recipe” 1 molecule N2 + 3 molecules H2 2 molecules NH3 “Macroscopic recipe” 1 mol N2 + 3 mol H2 2 mol NH3 Experimental Conditions Reactants Products Before reaction 1 mol N2 + 3 mol H2 2 mol NH3 2 molecules N2 3 molecules H2 0 molecules NH3 After reaction 1 molecules N2 0 molecules H2 2 molecules NH3 Nitrogen is in excess – or hydrogen is limiting reagent.

Synthesis Reaction Direct combination reaction (Synthesis) 2 Na + Cl2  2 NaCl Na Na Cl Cl  Cl Cl Na Na General form: A + B  AB element or element or compound compound compound

Synthesis Reaction Direct combination reaction (Synthesis) 2 Na + Cl2  2 NaCl Na Cl Na+ Cl - Cl Cl - Na+ Na General form: A + B  AB element or element or compound compound compound

Formation of a solid: AgCl AgNO3(aq) + KCl(aq)  KNO3 (aq) + AgCl(s)

Pb2+ Cl1- K1+ I1- Pb2+ Cl1- K1+ I1- Cl2 Pb I K KCl PbI2 + + lead (II) chloride + potassium iodide potassium chloride + lead (II) iodide Pb2+ Cl1- K1+ I1- Pb2+ Cl1- K1+ I1- Cl2 Pb + I K KCl + PbI2 (aq) (ppt) A reaction that yields an insoluble product, a precipitate, when two solutions are mixed Are a subclass of exchange reactions that occur between ionic compounds when one of the products is insoluble Used to isolate metals that have been extracted from their ores and to recover precious metals for recycling Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

Pb2+ Cl1- K1+ I1- Pb2+ Cl1- K1+ I1- Cl2 Pb I K KCl PbI2 + + A reaction that yields an insoluble product, a precipitate, when two solutions are mixed Are a subclass of exchange reactions that occur between ionic compounds when one of the products is insoluble Used to isolate metals that have been extracted from their ores and to recover precious metals for recycling lead (II) chloride + potassium iodide potassium chloride + lead (II) iodide Pb2+ Cl1- K1+ I1- Pb2+ Cl1- K1+ I1- Cl2 Pb + I K KCl + PbI2 (aq) (ppt) Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

Decomposition Reaction 2 H2O + 2 H2 O2 H H O O H + H O O H General form: AB A + B compound two or more elements or compounds

Single and Double Replacement Reactions Single-replacement reaction Mg + CuSO4  MgSO4 + Cu General form: A + BC  AC + B Double-replacement reaction CaCO3 + 2 HCl  CaCl2 + H2CO3 General form: AB + CD  AD + CB

Activity Series Element Reactivity Halogen Reactivity Foiled again – Printable Version of Activity Series Element Reactivity Ca Li Rb K Ba Ca Na Mg Al Mn Zn Cr Fe Ni Sn Pb H2 Cu Hg Ag Pt Au Foiled again – Aluminum loses to Calcium Halogen Reactivity F2 Cl2 Br2 I2 Objectives: To explain the concept of an activity series for metals. To predict whether a single-replacement reaction occurs by referring to the activity series. The Activity Series – Predicts the outcome of the single-displacement reactions – Arranges metal and hydrogen in decreasing order of their tendency to be oxidized – Active metals at the top of the series have the greatest tendency to lose electrons; these including alkali metals (Group 1), alkaline earths (Group 2), and Al (Group 13). – Inert metals at the bottom of the series have the lowest tendency to be oxidized; these include precious metals or coinage metals located in the lower-right portion of the metals in the periodic table. – Any element will reduce compounds of the elements below it in the series. – Only those metals that lie above hydrogen in the activity series dissolve in acids to produce H2.

TABLE OF SOLUBILITIES IN WATER aluminum ss s n i d ammonium barium calcium copper (II) iron (II) iron (III) lead magnesium mercury (I) mercury (II) potassium silver sodium zinc acetate bromide carbonate chloride chromate hydroxide iodide nitrate phosphate sulfate sulfide

TABLE OF SOLUBILITIES IN WATER aluminum ss s n i d ammonium barium calcium copper (II) iron (II) iron (III) lead magnesium mercury (I) mercury (II) potassium silver sodium zinc acetate bromide carbonate chloride chromate hydroxide iodide nitrate phosphate sulfate sulfide Legend SOLID AQUEOUS i = insoluble ss = slightly soluble s = soluble d = decomposes n = not isolated

TABLE OF SOLUBILITIES IN WATER aluminum s aq n d ammonium barium calcium ss copper (II) iron (II) iron (III) lead magnesium mercury (I) si mercury (II) potassium silver sodium zinc acetate bromide carbonate chloride chromate hydroxide iodide nitrate phosphate sulfate sulfide Legend s = solid aq = aqueous d = decomposes n = not isolated

TABLE OF SOLUBILITIES IN WATER aluminum s aq n d ammonium barium calcium ss copper (II) iron (II) iron (III) lead magnesium mercury (I) si mercury (II) potassium silver sodium zinc acetate bromide carbonate chloride chromate hydroxide iodide nitrate phosphate sulfate sulfide Legend s = solid aq = aqueous d = decomposes n = not isolated

TABLE OF SOLUBILITIES IN WATER aluminum ss s n i d ammonium barium calcium copper (II) iron (II) iron (III) lead magnesium mercury (I) mercury (II) potassium silver sodium zinc acetate bromide carbonate chloride chromate hydroxide iodide nitrate phosphate sulfate sulfide Legend s = solid aq = aqueous d = decomposes n = not isolated

Solubility Rules 1. Most nitrates are soluble. Most salts containing Group I ion and ammonium ion, NH4+, are soluble. Most chloride, bromide, and iodide salts are soluble, except Ag+, Pb2+ and Hg22+. 4. Most sulfate salts are soluble, except BaSO4, PbSO4, Hg2SO4, and CaSO4. Most hydroxides except Group 1 and Ba(OH)2, Sr(OH)2, and Ca(OH)2 are only slightly soluble. Most sulfides, carbonates, chromates, and phosphates are only slightly soluble. Ohn-Sabatello, Morlan, Knoespel, Fast Track to a 5 Preparing for the AP Chemistry Examination 2006, page 91

Potassium reacts with Water P O W !

Double Replacement Reaction K2CO3 (aq) Potassium carbonate + BaCl2 (aq) Barium chloride 2 KCl (aq) Potassium chloride + BaCO3 (s) Barium carbonate

Synthesis Reactions Photosynthesis 6 CO2 + H2O C6H12O6 + O2 6 6 Formation of water 2 H2 + O2 H2O 2 Formation of salt http://www.pdphoto.org/jons/pictures2/leaf_1_bg_010503.jpg http://www.uwsp.edu/geo/faculty/ritter/images/lithosphere/mass_wasting_erosion/rain_splash_NRCS_p0000003256_small.jpg http://whyfiles.org/111salt/images/salt_magn2.jpg A photomicrograph of common table salt © Carl J. Bowser, Department of Geology and Geophysics, University of Wisconsin, Madison 2 Na + Cl2 NaCl 2 General Form A + B C

Decomposition Reactions Hydrogen Peroxide 2 H2O2 H2O + O2 2 Electrolysis of water H2O H2 + O2 electricity 2 2 Nitrogen triiodide 2 NI3 N2 + I2 3 General Form AB A + B

Predict if these reactions will occur 3 Mg + AlCl3 2 2 Al + MgCl2 3 Can magnesium replace aluminum? YES, magnesium is more reactive than aluminum. Activity Series Al + MgCl2 No reaction Can aluminum replace magnesium? NO, aluminum is less reactive than magnesium. Therefore, no reaction will occur. Activity Series Order of reactants DOES NOT determine how they react. MgCl2 + Al No reaction The question we must ask is can the single element replace its counterpart? metal replaces metal or nonmetal replaces nonmetal.

Single-Replacement Reactions Activity Series Li Rb K Ba Ca Na Mg Al Mn Zn Cr Fe Ni Sn Pb H2 Cu Hg Ag Pt Au “Magic blue-earth” Fe + CuCl2 FeCl2 + Cu Can Fe replace Cu? Yes Zinc in nitric acid F2 Cl2 Br2 I2 Zn + HNO3 Zn(NO3)2 + H2 2 Can Zn replace H? Yes NO REACTION MgBr2 + Cl2 MgCl2 + Br2 Can Br replace Cl? No General Form A + BC AC + B

A. C5H12 + O2  CO2 + H2O 8 5 6 B. C22H46 2 + O2  CO2 + H2O 67 44 46 Write a balanced chemical equation for the following combustion reactions: A. C5H12 + O2  CO2 + H2O 8 5 6 B. C22H46 2 + O2  CO2 + H2O 67 44 46 C. C15H28 + O2  CO2 + H2O 22 15 14

Chemical Word Equations Keys http://www.unit5.org/chemistry/Equations.html

KOH(aq) + HNO3(aq) KNO3(aq) + H2O ? How would you prepare potassium nitrate (using a double replacement reaction)? potassium nitrate formation of water is a driving force. K K OH KOH + HNO3 KNO3 + H2O + H H NO3 KNO3 + H2O _________ _________ _________ Ca(NO3)2 Both potassium nitrate and calcium chloride are soluble (no driving force – no reaction!) 2 KOH + Ca(NO3)2 2 KNO3 + Ca(OH)2 Combine a potassium hydroxide solution with nitric acid to yield soluble potassium nitrate. KOH(aq) + HNO3(aq) KNO3(aq) + H2O ? The water could then be removed by distillation to recover solid potassium nitrate.

Fe2+ Cl1- Na1+ CO32- Fe2+ Cl1- Na1+ CO32- Cl2 Fe CO3 Na2 NaCl FeCO3 Predict if a reaction will occur when you combine aqueous solutions of iron (II) chloride with aqueous sodium carbonate solution. If the reaction does occur, write a balanced chemical equation showing it. (be sure to include phase notation) Balanced chemical equation iron (II) chloride + sodium carbonate sodium chloride + iron (II) carbonate Fe2+ Cl1- Na1+ CO32- Fe2+ Cl1- Na1+ CO32- Cl2 Fe CO3 Na2 NaCl FeCO3 (aq) (ppt) Using a SOLUBILITY TABLE: sodium chloride is soluble iron (II) carbonate is insoluble FeCl2 Na2CO3 NaCl FeCO3 (aq) (ppt) + 2 (aq) (aq) Complete Ionic Equation Fe2+(aq) + 2Cl1-(aq) + 2Na1+(aq) + CO32-(aq) 2Na1+(aq) + 2Cl1-(aq) + FeCO3(s)

Mole Calculations Objectives: To relate the moles of a substance to the number of particles. To relate the mass of a substance to the number of particles. To state the value for the molar volume of any gas at STP: 22.4 L/mol. To relate the density of a gas at STP to its molar mass and volume. To relate the volume of a gas at STP to its mass and number of particles.

Visualizing a Chemical Reaction 2 Na + Cl2 NaCl 2 ___ mole Na 10 10 ___ mole Cl2 5 5 ___ mole NaCl 10 10 ?

Formation of Ammonia N2 (g) + 3 H2 (g) 2 NH3 (g) + + + + + + + + 2 atoms N and 2 atoms N + 6 atoms H 6 atoms H 1 molecule N2 + 3 molecules H2 2 molecules NH3 10 molecule N2 + 30 molecules H2 20 molecules NH3 6.02 x 1023 molecules N2 6.02 x 1023 molecules H2 6.02 x 1023 molecules NH3 1 x + 3 x 2 x 1 mol N2 + 3 mol H2 2 mol NH3 28 g N2 + 3 x 2 g H2 2 x 17 g NH3 34 g reactants 34 g products Assume STP 22.4 L 22.4 L 22.4 L 22.4 L 22.4 L 22.4 L + 22.4 L N2 67.2 L H2 44.8 L NH3

Formation of Ammonia

Proportional Relationships 2 1/4 c. flour 1 tsp. baking soda 1 tsp. salt 1 c. butter 3/4 c. sugar 3/4 c. brown sugar 1 tsp vanilla extract 2 eggs 2 c. chocolate chips Makes 5 dozen cookies. Conversion Factor I have 5 eggs. How many cookies can I make? 2 1/4 cups all-purpose flour 1 tsp baking soda 1 tsp salt 1 cup (2 sticks) butter, softened 3/4 cup granulated sugar 3/4 cup packed brown sugar 1 tsp vanilla extract 2 eggs 2 cups (12 oz. package) chocolate morsels 1 cup chopped nuts (walnuts, pecans or macadamia) Preheat oven to 400oF.  Combine flour, baking soda and salt in bowl. Beat butter, granulated and brown sugars, and vanilla in large bowl until creamy.  Add eggs one at a time until smooth. Gradually add dry ingredients.  When well blended add morsels and nuts.  I prefer to hand stir at this point not to break or melt the chocolate morsels. Drop by tablespoon-fulls onto ungreased baking sheets, keeping about 2" apart.  Bake for 9 to 11 minutes until golden brown.  Cool on baking sheet for a couple of minutes and transfer to wire rack until completely cool, being sure to eat at least one while warm to ensure quality control! http://www.oldetimecooking.com/Images/Recipes/chocchipcookie.jpg Ratio of eggs to cookies 5 eggs 5 dozen 2 eggs = 12.5 dozen cookies 150 cookies Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Proportional Relationships Stoichiometry mass relationships between substances in a chemical reaction based on the mole ratio Mole Ratio indicated by coefficients in a balanced equation A balanced chemical equation gives the identity of the reactants and products and the accurate number of molecules or moles of each that are consumed or produced. Stoichiometry is a collective term for the quantitative relationships between the masses, numbers of moles, and numbers of particles (atoms, molecules, and ions) of the reactants and products in a balanced reaction. A stoichiometric quantity is the amount of product or reactant specified by the coefficients in a balanced chemical equation. 2 Mg + O2  2 MgO Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Stoichiometry Steps Core step in all stoichiometry problems!! 1. Write a balanced equation. 2. Identify known & unknown. 3. Line up conversion factors. Mole ratio - moles  moles Molar mass - moles  grams Molarity - moles  liters soln Molar volume - moles  liters gas Mole ratio - moles  moles Core step in all stoichiometry problems!! 4. Check answer. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Standard Temperature & Pressure Molar Volume at STP 1 mol of a gas=22.4 L at STP Standard Temperature & Pressure 0°C and 1 atm Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Molar Volume at STP MOLES LITERS OF GAS AT STP (22.4 L/mol) MASS IN GRAMS MOLES NUMBER OF PARTICLES Molar Mass (g/mol) 6.02  1023 particles/mol Molarity (mol/L) LITERS OF SOLUTION Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Stoichiometry Problems How many moles of KClO3 must decompose in order to produce 9 moles of oxygen gas? 2KClO3  2KCl + 3O2 ? mol 9 mol 9 mol O2 2 mol KClO3 3 mol O2 = 6 mol KClO3 Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

1. 2 Sb + 3 Cl2  2 SbCl3 2. 2 Mg + O2  2 MgO 3. CaCl2  Ca + Cl2 4. 2 NaClO3  2 NaCl + 3 O2 5. Fe + 2 HCl  FeCl2 + H2 6. CuO + H2  Cu + H2O 7. 2 Al + 3 H2SO4  Al2(SO4)3 + 3 H2

2 3 1. 2 Sb + 3 Cl2  2 SbCl3 = excess 5 mol 7.5 mol excess x mol How many moles of chlorine gas are required to react with 5 moles of antimony? 3 mol Cl2 x mol Cl2 = 5 mol Sb = 7.5 mol Cl2 2 mol Sb How many moles of SbCl3 are produced from 5 moles of antimony and excess Cl2? 2 mol SbCl3 x mol SbCl3 = 5 mol Sb = 5 mol SbCl3 2 mol Sb How many moles of SbCl3 are produced from 7.5 moles of Cl2 and excess Sb? 2 mol SbCl3 x mol SbCl3 = 7.5 mol Cl2 = 5 mol SbCl3 3 mol Cl2

2. 2 Mg + O2  2 MgO 10 mol x L x mol How many moles of magnesium oxide are produced from the burning of 10 mol of Mg? 2 mol MgO x mol MgO = 10 mol Mg = 10 mol MgO 2 mol Mg How many liters of oxygen are needed to burn 10 mol of Mg? Assume 1 mol O2 = 22.4 L 1 mol O2 22.4 L O2 x L O2 = 10 mol Mg = 5 mol O2 = 112 L O2 2 mol Mg 1 mol O2 1 mol O2 22.4 L O2 x L O2 = 10 mol Mg = 112 L O2 2 mol Mg 1 mol O2

calcium chloride calcium chlorine 3. CaCl2  Ca + Cl2 + 8 mol x mol How many moles of calcium metal are produced from the decomposition of 8 mol of calcium chloride? and chlorine gas 1 mol Ca x mol Ca = 8 mol CaCl2 = 8 mol Ca 1 mol CaCl2 How many moles of calcium metal and chlorine gas are produced from the decomposition of 8 mol of calcium chloride? http://www.amazingrust.com/Experiments/how_to/Images/Chlorine_gas.jpg 1 mol Cl2 x mol Cl2 = 8 mol CaCl2 = 8 mol Cl2 1 mol CaCl2

Quantitative Relationships in Chemical Equations Keys http://www.unit5.org/chemistry/Equations.html

Chemical Equations (Paragraph – Vocabulary) Keys http://www.unit5.org/chemistry/Equations.html

Real Life Chemistry (for the business world) Keys http://www.unit5.org/chemistry/Equations.html

Ions in Aqueous Solution Print Copy of Lab Pb(NO3)2(s) + H2O(l) Pb(NO3)2(aq) Pb2+(aq) + 2 NO31–(aq) Pb2+ NO31– Pb2+ NO31– add water in solution NO31– NO31– dissociation: NaI(s) + H2O(l) NaI(aq) Na1+(aq) + I1–(aq) Na1+ I1– Na1+ I1– Mix them and get… Balance to get overall ionic equation… Cancel spectator ions to get net ionic equation…

Balance to get overall ionic equation… Solubility Chart Mix them and get… Pb(NO3)2(aq) + 2 NaI(aq) PbI2 + NaNO3 PbI2(s) + 2 NO31–(aq) (s) (aq) + 2 Na1+(aq) Pb2+ NO31– Pb2+ I1– solid NO31– I1– Na1+ I1– Na1+ NO31– in solution Na1+ I1– Na1+ NO31– Balance to get overall ionic equation… Pb2+(aq) + 2 NO31–(aq) + 2 Na1+(aq) + 2 I1–(aq) PbI2(s) + 2 NO31–(aq) + 2 Na1+(aq) Cancel spectator ions to get net ionic equation… Pb2+(aq) + 2 I1–(aq) PbI2(s)

Mix together Zn(NO3)2(aq) and Ba(OH)2(aq): Solubility Chart Mix together Zn(NO3)2(aq) and Ba(OH)2(aq): Mix them and get… Ba(NO3)2 and Zn(OH)2 (aq) (ppt) Zn(NO3)2(aq) + Ba(OH)2(aq) Zn(OH)2(s) + 2 NO31–(aq) + Ba2+(aq) Zn(NO3)2(aq) Ba(OH)2(aq) Zn2+(aq) + 2 NO31–(aq) Ba2+(aq) + 2 OH1–(aq) NO31– OH1– Zn2+ Ba2+ NO31– OH1– Balance to get overall ionic equation… Zn2+(aq) + 2 NO31–(aq) + Ba2+(aq) + 2OH1–(aq) Zn(OH)2(s) + 2 NO31–(aq) + Ba2+(aq) Cancel spectator ions to get net ionic equation… Zn2+(aq) + 2 OH1–(aq) Zn(OH)2(s)

(NH4)3PO4 + Mg(OH)2  Mg3(PO4)2 3 + 6 NH4OH ? 2 (NH4)3PO4 + Mg(OH)2  Mg3(PO4)2 3 + 6 NH4OH ammonium phosphate magnesium hydroxide magnesium phosphate ammonium hydroxide NH41+ OH1- Now you try… 2 AlCl3 + Li2CO3  Al2(CO3)3 + LiCl 3 6

Al2(SO4)3(aq) + 6 NH4OH(aq)  2 Al(OH)3 + 3 (NH4)2SO4 (ppt) (aq) Identify the spectator ions and write a net ionic equation when an aqueous solution of aluminum sulfate is mixed with aqueous ammonium hydroxide. Al3+ SO42- NH41+ OH1- Al3+ OH1- NH41+ SO42- sulfate + hydroxide  aluminum aluminum ammonium ammonium aluminum hydroxide + ammonium sulfate Al2(SO4)3(aq) + 6 NH4OH(aq)  2 Al(OH)3 + 3 (NH4)2SO4 (ppt) (aq) 2 Al3+(aq) + 3 SO42-(aq) + 6 NH41+(aq) + 6 OH1-(aq)  2 Al(OH)3(ppt) + 6 NH41+(aq) + 3 SO42-(aq) “spectator ions” 2 Al3+(aq) + 6 OH1-(aq)  2 Al(OH)3(ppt) Net Ionic Equation

Ions In Solution Lab Ions in Solution Ions in Solution Keys http://www.unit5.org/chemistry/Equations.html

Meaning of Coefficients 2 atoms Na 1 molecule Cl2 2 molecules NaCl 2 Na + Cl2 2 NaCl 2 g sodium + 1 g chlorine = 2 g sodium chloride 2 mol sodium 1 mol chlorine 2 mol sodium chloride (2 mol Na) x (23 g/mol) (1 mol Cl2) x (71 g/mol) (2 mol NaCl) x (58.5 g/mol) 46 g 71 g 117 g 117 g

Classes of Reactions Chemical reactions Precipitation reactions Oxidation-Reduction Reactions Acid-Base Reactions Combustion Reactions

Summary of Classes of Reactions Chemical reactions Precipitation reactions Oxidation-Reduction Reactions Acid-Base Reactions Combustion Reactions Synthesis reactions (Reactants are elements.) Decomposition reactions (Products are elements.)

Summary of Classes of Reactions Chemical reactions Precipitation reactions Oxidation-Reduction Reactions Acid-Base Reactions Combustion Reactions Synthesis reactions Decomposition reactions

IONIC BONDING: Formation of Magnesium Chloride Cl Cl Mg Mg2+ Cl Cl Loses 2e- Each gains 1e- One magnesium ion Two chloride ions Mg2+ Cl1- [(2+) 2 (1-) = 0] MgCl2 magnesium chloride

IONIC BONDING: Formation of Magnesium Chloride Cl Cl Mg2+ Mg Mg2+ Cl Cl Loses 2e- Each gains 1e- One magnesium ion Two chloride ions Mg2+ Cl1- [(2+) 2 (1-) = 0] MgCl2 magnesium chloride

Production of Methanol CO H2 2 H2 CH3OH +

A Mixture of Molecules

KEYS – Chemical Equations and Reactions Worksheet - vocabulary Worksheet – Balancing Chemical Equations Worksheet – Chemical Word Equations Worksheet – Quantitative Relationships in Chem. Eqns. Worksheet – Chemical Equations (paragraph) Worksheet – Real Life Chemistry Worksheet – Balancing Equations (visual) Worksheet - Lab – Ions in Solution Textbook - questions Outline (general)

Resources - Chemical Equations and Reactions Worksheet - vocabulary Worksheet – Balancing Chemical Equations Worksheet – Chemical Word Equations Worksheet – Quantitative Relationships in Chem. Eqns. Worksheet – Chemical Equations (paragraph) Worksheet – Real Life Chemistry Worksheet – Balancing Equations (visual) Worksheet - Lab – Ions in Solution Textbook - questions Outline (general)