4 How Big is a Mole?N=6.022x1023One mole of Marshmallows would cover the entire earth 12 miles highOne mole of marshmallows would fill the Grand Canyon and still be enough left over to displace all the water from Lake Michigan and more
5 Moles as Conversion factors Grams to molesUse Molar MassEx: How many moles are in 9.01 g of water?Moles to molecules or atomsUse Avogadro’s numberEx: How many molecules of water are in 9.01 g of water?
6 Using Avogadro’s number Nicotine, a poisonous compound found in tobacco leaves, is 74.0% C, 8.65% H, and 17.35% N. It has a molar mass of 162 g/mol.What is the molecular formula of nicotine?The “average” cigarette in the US contains 9.0 mg of nicotine but during smoking about 90% of the nicotine is burned off.How many molecules of nicotine are inhaled during smoking of one “average” cigarette?
7 MolarityHow would you prepare 1 liter of a 0.25 M (molar) solution of glucose (C6H12O6) (molar mass 180 g/mol)?
8 Balancing Chemical Equations 2H O2 2H2O2 atoms hydrogen forms 2 molecules+ water1 atom oxygen
9 Law of Conservation of Matter Matter can not be created nor destroyed.2H O2 2H2OSo 2 grams of hydrogen + 1 gram of oxygen does not form 2 grams of water
10 Balancing chemical equations the OHO method O - OtherH- HydrogenO- Oxygen
11 Combustion reactions Balance the following reactions Methane + oxygen carbon dioxide and waterMethanol (CH3OH) burns in oxygen to form carbon dioxide and water
12 Balance the following chemical reactions Sodium sulfate and calcium nitrate react to form sodium nitrate and calcium sulfateWrite a balanced equation for the reaction between aqueous solutions of potassium chromate and silver nitrate. The products of the reaction are solid silver chromate and a solution of potassium nitrate
13 Stoichiometry Moles A Moles B Grams A Moles A Moles B Moles B Grams B
14 Stoichiometry Mole to Mole Chlorine reacts with sodium to form sodium chloride. How many moles of sodium chloride are produced from 2.25 moles of chlorine?A 0.50 mol sample of solid KClO3 decomposes to give solid KCl and gaseous oxygen. How many moles of KCl will be produced?
15 Stoichiometry mass to mass Phosphorus reacts with oxygen to produce diphosphorus pentoxide. What is the mass of product formed from 20.0 g phosphorus?Aluminum reacts with sulfur to produce aluminum sulfide. How many grams of sulfur are required to react with 4.80 grams of aluminum?
16 Limiting Reactantfor reactions with multiple reactants, it is likely that one of the reactants will be completely used before the otherswhen this reactant is used up, the reaction stops and no more product is madethe reactant that limits the amount of product is called the limiting reactantsometimes called the limiting reagentthe limiting reactant gets completely consumedreactants not completely consumed are called excess reactantsthe amount of product that can be made from the limiting reactant is called the theoretical yield
17 Put more simply: What is the theoretical yield of hamburgers in the above reaction?
18 Limiting and Excess Reactants in the Combustion of Methane CH4(g) + 2 O2(g) ® CO2(g) + 2 H2O(g)Our balanced equation for the combustion of methane implies that every 1 molecule of CH4 reacts with 2 molecules of O2HC+O
19 Limiting and Excess Reactants in the Combustion of Methane CH4(g) + 2 O2(g) CO2(g) + 2 H2O(g)If we have 5 molecules of CH4 and 8 molecules of O2, which is the limiting reactant?HC+O?
21 Stoichiometry (sample problems) 3 CS2 + 6 NaOH 2 Na2CS3 + Na2CO H2OIf mol of CS2 reacts with 1.00 mol NaOH how many moles of each product are formed?How many grams of Na2CS3 are produced in the reaction of 88.0 mL of liquid CS2 (d=1.26g/mL) and 3.12 mol NaOH
22 Stoichiometry(sample problems) What mass of H2 is produced by the reaction of 2.14 g Al with 75.0 mL of 2.90 M HCl?2 Al HCl 3H AlCl3
25 Percent yield C6H6(l) + Cl2(g) C6H5Cl(l) + HCl(g) Chlorobenzene, a starting material in the production of aspirin and other compounds is prepared from benzene by the following reactionC6H6(l) + Cl2(g) C6H5Cl(l) + HCl(g)benzene chlorobenzeneA 10.0 kg sample of benzene treated with excess chlorine gas yields 10.4 kg of chlorobenzene. Calculate the % yield.
26 Actual and theoretical yields A laboratory manual calls for 13.0 g C4H9Br, 21.6 g NaBr, and 33.8 g H2SO4 as reactants in this reactionC4H9Br + NaBr + H2SO4 C4H9Br NaHSO4 + H2OA student following these directions obtains 16.8 g C4H9Br. What are (a) the theoretical yield (b) the actual yield and (c) the percent yield in the reaction?