Unit 5 Chemical Equations And Reactions
Unit 5Chemical Equations and ReactionsWhat is a Chemical Equation?A Chemical Equation is a written representation of theprocess that occurs in a chemical reaction. A chemical equation iswritten with the Reactants on the left side of an arrow and theProducts of the chemical reaction on the right side of theequation. The head of the arrow typically points toward theright or toward the product side of the equation, although reactions may indicate equilibrium with thereaction proceeding in both directions simultaneously.The elements in an equation are denoted using their symbols. Coefficients next to thesymbols indicate the stoichiometric numbers. Subscripts are used to indicate the number ofatoms of an element present in a chemical species.An example of a chemical equation may be seen in the combustion of methane:CH4 2 O2 CO2 2 H2OBalancing Equations NotesAn equation for a chemical reaction in which the number of atoms for each element in the reaction andthe total charge are the same for both the reactants and the products. In other words, the mass and thecharge are balanced on both sides of the reaction.Symbol Meaningused to separate one reactant or product from anotherused to separate the reactants from the products - it ispronounced "yields" or "produces" when the equation is readused when the reaction can proceed in both directions - this iscalled an equilibrium arrow and will be used later in the course(g)indicates that the substance is in a gaseous statean alternative way of representing a substance in a gaseous state(s)indicates that the substance is in a solid statean alternative way of representing a substance in a solid state(aq)(l)indicates that the substance is dissolved in water - the aq comesfrom aqueousIdentifies a phase state as pure liquidindicates that heat is applied to make the reaction proceed1
LAW OF CONSERVATION OF MASSIn all chemical equations the LAW OF CONSERVATION OF MASS must be met.Matter can NOT be created nor destroyed in a chemical reaction.Remember, in a chemical reaction, the atoms/ions are simply rearranged to formnew substances.Therefore, chemical equations MUST be balanced.WHAT IS A “BALANCED” CHEMICAL EQUATION?A balanced chemical equation is one in which each side of the equation has thesame number of atoms/ions of each element.Example:Al (s) O2 (g) Al2O3 (s)Not Balanced1 Al2 Al2 O3 O4 Al (s) 3 O2 (g)Balanced4 Al6 O 2 Al2O3 (s)4 Al6 ORULES FOR BALANCING CHEMICAL EQUATIONS1.Write the correct chemical formulas for all of the reactants and theproducts.2.Write the formulas of the reactants on the LEFT of the reaction arrow;write the formulas of the products on the RIGHT of the reaction arrow.3.COUNT the total number of atoms/ions of each element in the reactantsand the total number of atoms/ions of each element in the products.** A polyatomic ion that appears unchanged on both sides of theequation is counted as a single unit.4.Balance the elements one at a time using coefficients. A coefficient is a small WHOLE number that is written in front of achemical formula in a chemical equation.2
When no coefficient is written, the coefficient is assumed to be 1. It is best to begin with elements OTHER THAN hydrogen and oxygen.These elements often occur more than twice in equations. ** You must NOT attempt to balance the equation by changingsubscripts in chemical formulas!!!!!!5.Check each atom/ion, or polyatomic ion to be sure that the equation iscorrectly balanced.6.Finally, make sure that all of the coefficients are in the LOWEST possiblewhole number ratios. (At least one of the coefficients must be a primenumber!)Use coefficients to make sure the number of atoms is the same on both sides of theequation.1. 2 H2 O2 2 H2O2. 2 HCl Zn ZnCl2 H23. 2 Al 3 CaS Al2S3 3 Ca4.Write the skeleton equation for the reaction of solid Iron and gaseouschlorine react to produce a sol as and watervapor.2 C3H7OH(l ) 9 O2 6CO2 (g) 8 H2O*note that C3H7OHis a Liquid(l )4. Aluminum metal reacts with oxygen gas to form solid aluminum oxide.4 Al 3 O2 (g) 2 Al2O3 (s)5. Liquid carbonic acid (hydrogen carbonate) decomposes into carbon dioxide gas andwater.H2CO3 CO 2 (g)H2O6. Lead (II) nitrate solution reacts with iron (III) chloride solution to form solid lead (II)chloride and Iron (III) nitrate solution.3 Pb(NO3)2 (aq) 2 FeCl3 (aq) 3 PbCl2 (aq) 2 Fe(NO3)3 (aq)7. Aluminum metal reacts with silver sulfate solution to form aluminum sulfate solutionand silver metal.2 Al 3 Ag SO4 (aq) Al2(SO4)3 (aq) 3 Ag8. Methane gas (CH4) reacts with oxygen gas to form carbon dioxide gas and water vapor.CH4 2 O2 (g) CO2 (g) 2 H2O (g)9. Iron metal reacts with bromine gas to form iron (III) bromide solid.2 Fe 3 Br2 (g) 2 Fe Br310. Hydrogen peroxide solution decomposes into water and oxygen gas.2 H2O2 (aq) 2 H2O O2 (g)12
Polarity of molecules Videohttps://www.youtube.com/watch?v PVL24HAesncPOLAR AND NON POLAR COVALENT MOLECULES, POLAR VS. NONPOLAR - CLEAR & SIMPLEUsing modelshttps://www.youtube.com/watch?v uYtwU0uRK7o13
Rules for Predicting Products of Chemical Reactions1. Hydrocarbon O2a. 2C4H10 13 O2CO2 H2O (Combustion)8 CO2 10 H2O2. Metal CarbonateMetal Oxide CO2 (Decomposition)a. MgCO3MgO CO2b. Synthesis: Metal Oxide CO2Metal Carbonate3. Metal SulfitesMetal Oxide SO2 (Decomposition)a. CaSO3CaO SO2b. Synthesis: Metal Oxide SO2Metal Sulfite4. Metal Hydride H2OMetal Hydroxide H2 (Double Replacement)a. KH H2OKOH H25. Metal H2OMetal Hydroxide H2 (Single Replacement)a. 2Na 2H2O2NaOH H26. Metal Oxide H2Oa. MgO H2OMetal Hydroxide (Synthesis)Mg(OH)27. Non-metal oxide H2Oternary acid (Synthesis)a. N2O3 H2O2 HNO2b. N2O5 H2O2 HNO3c. CO2 H2OH2CO314
Predicting Products:Write the COMPLETE balanced equation1. Hydrochloric acid (HCl) reacts with sodium hydroxide.HCl NaOH 2O (rememberNaClHOH is alsoH 2HO)2. Sodium reacts with oxygen4Na O2 2Na2O3. Mercury (II) oxide 2HgO 22Hg O4. Zinc reacts with lead (II) NitrateZn Pb(NO(NO3)23)2 Pb Zn5. Silver nitrate reacts with calcium chloride2 AgNO3 CaCl2 2AgCl Ca(NO3)26. C7H16 reacts with oxygenC7H16 11 O2 7CO2O 8H27. CH3OH reacts with oxygen2 CH3OH 3 O2 2 H2O 4 CO28. Magnesium reacts with FluorineMg F2 2MgFCu2 9. Copper (II) Chloride CuCl2 Cl10.Aluminum reacts with Calcium Sulfide2 Al 3 CaS2S3 3 CaAl11.Potassium Hydroxide reacts with Zinc Chloride2 KOH ZnCl2 2 KCl Zn(OH)212.C2H2 reacts with oxygen2 C2H2 5O2 2H2O 4CO213.Sodium Iodide reacts with chlorine2 NaI Cl2 2NaCl2 14.Aluminum reacts with sulfur2Al 3S 2S3Al15I
Unit 5 TestReviewDetermine the formula for the compound formed by the two atoms and indicate if it isan ionic or covalent compound1. Calcium and Oxygen2. Nitrogen and FluorineCaONF33. Sodium and ChlorineNaCl4. Carbon and OxygenCO2Draw the dot diagram for each of the IONIC compounds below5. CaO6. Na2S7. SrF210. KIComplete the table below.FormulaElectron DotDiagramBondingOrbitalsShapeStructural Formula tY316Y
sp3CH3FTetrahedralYVSPER Worksheet:1)What is the main idea behind VSEPR theory?It is a set of rules whereby the chemist may predict the shape of an isolated molecule. It isbased on the premise that groups of electrons surrounding a central atom repel eachother, and that to minimize the overall energy of the molecule, these groups of electronstry to get as far apart as possible.2)For each of the following compounds, draw the Lewis diagram, structural diagram and name themolecular shapes, and for all atoms:a)carbon tetrachlorideCCl4b)BH3c)silicon disulfideSiS2d)PF3e)carbon dioxideTetrahedralTrigonal PlanarLinearTrigonal PyramidLinearCO2f)SF2Bent17
Balance the following equations:1. 6 HCl 2 O ĺ 2 AlCl3 3 H22. 4 HNO3 Zn ĺ Zn(NO3)2 2 NO2 2 H2O3. 4 HNO3 Sn ĺ SnO2 4 NO2 2 H2OWrite the balanced equation for the following chemical reaction AND the type ofreaction that has occurred.4. Sodium metal is added to sulfuric acid and produce sodium sulfate and hydrogen.2 Na (s) H2SO4 (aq) Na2SO4 H2 (g) Single Replacement5. White phosphorus (P4) reacts with chlorine to make phosphorus trichlorideP4 (s) 6 Cl2 (g) 4 PCl3 (g) Synthesis6. Magnesium chlorate, is heated strongly until it decomposes into magnesium chlorideand oxygen gas.Mg(ClO3)2 (s) MgCl2 (s) 3 O2 (g) DecompositionWrite the balanced equation for the product AND the type of reaction that hasoccurred.7. Butane gas (C4H10) is burned completely in air.2 C4H10 (g) 13 O2 (g) 8 CO2 (g) 10 H2O (g) Combustion8. Iron metal is added to bromine2 Fe (s) 3 Br2 (l) 2 FeBr3 (s) Synthesis9. Calcium metal is added to phosphoric acid.3 Ca (s) 2 H3PO4 (aq) Ca3 (PO4)2 (s) 3 H2 (g) Single Replacement10. Aluminum metal is added to a solution of iron (III) chloride.Al(s) FeCl3 (aq) AlCl3(aq) Fe(s) Single Replacement11. A piece of iron metal is exposed to oxygen gas (Fe product would form).4 Fe (s) 3 O2 (g) 2 Fe2O3(s) Synthesis12. Calcium metal is added to water.Ca (s) 2 H2O (l) Ca(OH)2 (s) H2 (g) Single Replacement13. Potassium metal reacts with chlorine gas.2 K (s) Cl2 (g) 2 KCl (s) Synthesis18
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1 Unit 5 Chemical Equations and Reactions What is a Chemical Equation? A Chemical Equation is a written representation of the process that occurs in a chemical reaction. A chemical equation is written with the Reactants on the left side of an arrow and the Products of
Chemical Formulas and Equations continued How Are Chemical Formulas Used to Write Chemical Equations? Scientists use chemical equations to describe reac-tions. A chemical equation uses chemical symbols and formulas as a short way to show what happens in a chemical reaction. A chemical equation shows that atoms are only rearranged in a chemical .
EQUATIONS AND INEQUALITIES Golden Rule of Equations: "What you do to one side, you do to the other side too" Linear Equations Quadratic Equations Simultaneous Linear Equations Word Problems Literal Equations Linear Inequalities 1 LINEAR EQUATIONS E.g. Solve the following equations: (a) (b) 2s 3 11 4 2 8 2 11 3 s
Word & Chemical Equations Scientists represent chemical reactions in two ways: Word equations – uses chemical names, plus signs, and an arrow to show the reaction. Example: Chemical equations – uses chemical formulas, plus signs, and an arrow to show the reaction.States of matter are also shown in subscripts after each chemical substance. Example:
C.P. Chemistry Test Unit 8 Study Guide Chemical Equations and Reactions Recognize evidence of chemical change. Identify the reactants and products in a chemical reaction. Represent chemical reactions with equations. Know what is represented by the symbols: s, l, g, and aq. Categorize chemical reactions by type (synthesis/combination, decomposition,
1.2 First Order Equations 5 1.3 Direction Fields for First Order Equations 14 Chapter 2 First Order Equations 2.1 Linear First Order Equations 27 2.2 Separable Equations 39 2.3 Existence and Uniqueness of Solutions of Nonlinear Equations 48 2.5 Exact Equations 55 2.6 Integrating Factors 63 Chapter 3 Numerical Methods 3.1 Euler’s Method 74
Chapter 1 Introduction 1 1.1 ApplicationsLeading to Differential Equations 1.2 First Order Equations 5 1.3 Direction Fields for First Order Equations 16 Chapter 2 First Order Equations 30 2.1 Linear First Order Equations 30 2.2 Separable Equations 45 2.3 Existence and Uniqueness of Solutionsof Nonlinear Equations 55
point can be determined by solving a system of equations. A system of equations is a set of two or more equations. To ÒsolveÓ a system of equations means to find values for the variables in the equations, which make all the equations true at the same time. One way to solve a system of equations is by graphing.
solving equations from previous grades and is a gateway into the entire unit on equations and inequalities. Conceptual Understanding: Mystery Letters 4-5 days I will review equations by Conceptual Understanding:Solving simple equations, multi-step equations, and equations
