Chem 1131 1st EditionExam # 4 Study Guide Chapters 8,9Chapter 8: Chemical ReactionThe Reaction TypesCombustion: a substance burns in the presence of oxygen. Combustion of a compound that contains C and H (or C, H, and O) produces carbon dioxide gas and water.e.g. CH2O(l) + O2(g) → CO2(g) + H2O(l)Combination: two or more reactants combine to form a single product.e.g. NH3(g) + HCl(g) → NH4Cl(s)Decomposition: Reactant breaks down to form two or more products.e.g. CaCO3(s) → CaO(s) + CO2(g)Empirical Formula of a CompoundCombustion of a 5.50-g sample of benzene produces 18.59g CO2 and 3.81g H2O. Determine the empirical formula and the molecular formula of benzene, given that its molar mass is approximately 78g/mol. converting C0.4224H0.423 to the whole number gives the empirical formula C Molecular formula: molar mass (78g) / empirical formula mass (atomic mass of C+H=13.02amu)gives 6. Multiplying both subscripts in the empirical formula by 6 gives the molecular formula C6H6Reactants and Products CalculationDinitrogen monoxide (N2O), also known as nitrous oxide or “laughing gas,” is used as an anesthetic in dentistry. It is manufactured by heating ammonium nitrate.% yield = actual yieldtheoretical yield´ 100%The balanced equation is NH4NO3(s) → N2O(g) + 2H2O(l)Formula masses (NH4NO3= 80.05 amu , N2O = 44.02 amu, H2O = 18.02 amu)Calculate the mass of ammonium nitrate that must be heated in order to produce 10.0 g of nitrousoxide and determine the corresponding mass of water produced in the reaction.Thus, 18.2g of ammonium nitrate must be hated to produce 10.0g of nitrous oxide8.19g of water will be produced.Limiting ReactantsLimiting reactant: the reactant used up first in a reaction. The amount of this reactant limits the amount of product that can from. Excess reactants: those present in quantities greater than necessary to react with the quantity of the limiting reactant. Consider a reaction between 5 moles of CO and 8 moles of H2 to produce methanol. How many moles of H2 are necessary in order for all the CO to react? How many moles of CO are necessary in order for all of the H2 to react? 10 moles of H2 required; 8 moles of H2 available; limiting reactant. 4 moles of CO required; 5 moles of CO available; excess reactant.Theoretical yield, Actual yield, Percent yieldTheoretical yield: the amount of product that forms when all the limiting reactant reacts to form the desired product. Actual yield: the amount of product actually obtained from a reaction. Percent yield: tells what percentage the actual yield is of the theoretical yield.In a certain aspirin synthesis, 104.8g of salicylic acid and 110.9g of acetic anhydride are combined. Calculate the theoretical yield and percent yield of the acetylsalicylic acid.Thus, theoretical yield of the acetylsalicylic acid is 136.7g percent yield = (105.6g/136.7g) x 100% = 77.25%Chapter 9: Chemical Reaction in Aqueous SolutionCategorizing CompoundNon-electrolyte: a substance that dissolves in water to yield a solution that does not conduct electricity Weak electrolyte: a compound that produces ions upon dissolving but exists in solution predominantly as molecules that are not ionized. Strong electrolyte: An electrolyte that dissociates completely. All water-soluble ionic compoundsfall into this category.How to figure out if compound is non-electrolyte, weak electrolyte, or strong electrolyte?Acid and BasesAcid: produce H+ Base: produce OH-Solubility Rules Solubility: the maximum amount of solute that will dissolve in a given quantity of solvent at a specific temperature.Precipitate: An insoluble product that separates from a solutione.g. 2NaI(aq) + Pb(NO3)2(aq) PbI2( s ) + 2NaNO3(aq)Molecular, Ionic and net Ionic EquationsMolecular equation: compounds are represented by chemical formulas as though they exist in solution as molecules or formula units.Ionic equation: compounds exist completely or predominately as ions in solution are represented as those ions.Net ionic equation: An equation that includes only the species that are actually involved in the reactionSpectator ion: Ions that appear on both sides of the equationArrhenius and Bronsted acids and basesArrhenius Acid: one that ionizes in water to produce H+ ions.e.g. Arrhenius Base: one that dissociates in water to produce OH– ions.Bronsted Acid: a proton donorBronsted Base: a proton receptorIn these definitions, a proton refers to a hydrogen atom that has lost its electron—also known as a hydrogen ion (H+).NH3 is a Brønsted base because it accepts a proton to become NH4 H2O is a Brønsted acid because it donates a proton to become OH–Neutralization ReactionNeutralization Reaction: a reaction between an acid and a base. Generally, a neutralization reaction produces water and a salt.Oxidation Reduction reactionOxidation-reduction reaction: a chemical reaction in which electrons are transferred from one reactant to another. Oxidation is the loss of electrons, and reduction is the gain of electrons.Oxidation Number RulesThe oxidation number: the charge an atom would have if electrons were transferred completely.To assign oxidation numbers:The oxidation number of an element, in its elemental form, is zero. The oxidation numbers in anychemical species must sum to the overall charge on the species.must sum to zero for any moleculemust sum to the charge on any polyatomic ionthe oxidation number of a monoatomic ion is equal to the charge on the ionOxidation of Metals in Aqueous SolutionActivity series: a list of metals (and hydrogen) arranged from top to bottom in order of decreasing ease of oxidation.Metals listed at the top are called active metals.Metals listed at the bottom are called noble metals (relatively unreactive).An element in the series will be oxidized by the ions of any element that appears below it in the table.Zn(s) + CuCl2(aq) → ZnCl2(aq) + Cu(s)Molarity, Dilution, TitrationMolarity: defined as the number of moles of solute per liter of solution.Dilution: the process of preparing a less concentrated solution from a more concentrated one.Titration: quantitative studies of