Chapter SixOutlineGoalsGoals Contd.6.1 Chemical EquationsSlide 66.2 Balancing Chemical EquationsSlide 8Slide 96.3 Avogadro’s Number and the Mole6.4 Gram – Mole ConversionsSlide 126.5 Mole Relationships and Chemical EquationsSlide 146.6 Mass Relationships and Chemical EquationsSlide 16Slide 176.7 Limiting Reagent and Percent YieldSlide 196.8 Classes of Chemical ReactionsSlide 216.9 Precipitation Reactions and Solubility GuidelinesSlide 236.10 Acids, Bases, and Neutralization Reactions6.11 Redox ReactionsSlide 26Slide 276.12 Recognizing Redox ReactionsSlide 29Slide 30Slide 316.13 Net Ionic EquationsChapter SummaryChapter Summary Contd.Slide 35Key WordsKey Words Contd.Slide 38Chapter SixChemical Reactions:Classification and Mass RelationshipsFundamentals of General, Organic and Biological Chemistry 6th EditionJames E. MayhughCopyright © 2010 Pearson Education, Inc.Copyright © 2010 Pearson Education, Inc.Chapter Six2Outline►6.1 Chemical Equations►6.2 Balancing Chemical Equations►6.3 Avogadro’s Number and the Mole►6.4 Gram–Mole Conversions►6.5 Mole Relationships and Chemical Equations►6.6 Mass Relationships and Chemical Equations►6.7 Limiting Reagent and Percent Yield►6.8 Classes of Chemical Reactions►6.9 Precipitation Reactions and Solubility Guidelines►6.10 Acids, Bases, and Neutralization Reactions►6.11 Redox Reactions►6.12 Recognizing Redox Reactions►6.13 Net Ionic EquationsCopyright © 2010 Pearson Education, Inc.Chapter Six3Goals►1. How are chemical reactions written? Given the identities of reactants and products, be able to write a balanced chemical equation or net ionic equation.►2. What is the mole, and why is it useful in chemistry? Be able to explain the meaning and uses of the mole and Avogadro’s number.►3. How are molar quantities and mass quantities related? Be able to convert between molar and mass quantities of an element or compound.Copyright © 2010 Pearson Education, Inc.Chapter Six4Goals Contd.►4. What are the limiting reagent, theoretical yield, and percent yield of a reaction? Be able to take the amount of product actually formed in a reaction, calculate the amount that could form theoretically, and express the results as a percent yield.►5. How are chemical reactions of ionic compounds classified? Be able to recognize precipitation, acid–base neutralization, and redox reactions.►6. What are oxidation numbers, and how are they used? Be able to assign oxidation numbers to atoms in compounds and identify the substances oxidized and reduced in a given reaction.Copyright © 2010 Pearson Education, Inc.Chapter Six56.1 Chemical Equations►Chemical equation: An expression in which symbols are used to represent a chemical reaction.►Reactant: A substance that undergoes change in a chemical reaction and is written on the left side of the reaction arrow in a chemical equation.►Product: A substance that is formed in a chemical reaction and is written on the right side of the reaction arrow in a chemical equation.Copyright © 2010 Pearson Education, Inc.Chapter Six6►The numbers and kinds of atoms must be the same on both sides of the reaction arrow.►Numbers in front of formulas are called coefficients, they multiply all the atoms in a formula. ►The symbol 2 NaHCO3 indicates two units of sodium bicarbonate, which contains 2 Na,2 H, 2 C, and 6 O. ►Substances involved in chemical reactions may be solids, liquids, gases, or they may be in solution. ►This information is added to an equation by placing the appropriate symbols after the formulas:►Solid=(s) Liquid=(l) Gas=(g) Aqueous solution=(aq)Copyright © 2010 Pearson Education, Inc.Chapter Six76.2 Balancing Chemical Equations►Balancing chemical equations can be done using four basic steps:►STEP 1: Write an unbalanced equation, using the correct formulas for all reactants and products. ►STEP 2: Add appropriate coefficients to balance the numbers of atoms of each element.Copyright © 2010 Pearson Education, Inc.Chapter Six8►A polyatomic ion appearing on both sides of an equation can be treated as a single unit.►STEP 3: Check the equation to make sure the numbers and kinds of atoms on both sides of the equation are the same.Copyright © 2010 Pearson Education, Inc.Chapter Six9►STEP 4: Make sure the coefficients are reduced to their lowest whole-number values. ►The equation:2 H2SO4 + 4 NaOH  2 Na2SO4 + 4 H2O is balanced, but can be simplified by dividing all coefficients by 2:H2SO4 + 2 NaOH  Na2SO4 + 2 H2O►Hint: If an equation contains a pure element as a product or reactant it helps to assign that element’s coefficient last.Copyright © 2010 Pearson Education, Inc.Chapter Six106.3 Avogadro’s Number and the Mole►Molecular weight: The sum of atomic weights of all atoms in a molecule. ►Formula weight: The sum of atomic weights of all atoms in one formula unit of any compound.►Mole: One mole of any substance is the amount whose mass in grams (molar mass) is numerically equal to its molecular or formula weight.►Avogadro’s number: The number of molecules or formula units in a mole. NA = 6.022 x 1023Copyright © 2010 Pearson Education, Inc.Chapter Six116.4 Gram – Mole Conversions►Molar mass = Mass of 1 mole of a substance.= Mass of 6.022 x 1023 molecules of a substance.= Molecular (formula) weight of substance in grams.►Molar mass serves as a conversion factor between numbers of moles and mass. If you know how many moles you have, you can calculate their mass; if you know the mass of a sample, you can calculate the number of moles.Copyright © 2010 Pearson Education, Inc.Chapter Six12The molar mass of water is 18.0 g. The conversion factor between moles of water and mass of water is 18.0 g/mol and the conversion factor between mass of water and moles of water is 1 mol/18.0 g:Copyright © 2010 Pearson Education, Inc.Chapter Six136.5 Mole Relationships and Chemical EquationsThe coefficients in a balanced chemical equation tell how many molecules, and thus how many moles, of each reactant are needed and how many molecules, and thus moles, of each product are formed. See the example below:Copyright © 2010 Pearson Education, Inc.Chapter Six14►The coefficients can be put in the form of mole ratios, which act as conversion factors when setting up factor-label calculations. ►In the ammonia synthesis the mole ratio of H2 to N2 is 3:1, the mole ratio of H2 to NH3 is 3:2, and the mole ratio of N2 to NH3 is 1:2 leading to the