What mass of CO is required to react with 146 g of iron III oxide Fe 2 O 3 3 CO 2 Fe 3 CO 2 146 g Fe2O3 159 69 g mol 0 914 moles Fe2O3 0 914 moles Fe2O3 3 moles of CO 1 mole of Fe2O3 2 74 moles CO 2 74 moles CO x 28 0 g mol 76 7 g CO 146 g Fe2O3 1 mole Fe2O3 159 69 g Fe2O3 3 moles CO 1 mole Fe2O3 28 0 g CO 1 mole CO 76 7 g CO 1 Clicker question What mass of iron III oxide reacted with excess carbon monoxide if the carbon dioxide produced by the reaction had a mass of 8 65 grams Fe 2 O3 3 CO D 2 Fe 3 CO 2 8 65 g CO2 44 0 g mol 0 1965 moles CO2 1 Fe2O3 3CO2 0655 moles Fe2O3 x 159 69 g mol 10 46 10 5 g Fe2O3 2 The limiting reactant reagent concept Substance that is used up first is the limiting reactant It limits the amount of product that can be formed Limiting Reactant Concept Suppose a box contains 87 bolts 110 washers and 99 nuts How many sets each consisting of one bolt two washers and one nut can you construct from the contents of one box 110 55 2 washers washers limiting reactant 4 How many moles of HCl can be produced by reacting 4 0 mol of H2 and 3 5 mol of Cl2 Which compoundd is the limiting reactant 1 Write formula H2 Cl2 2HCl 2 4 0 moles of H2 2 HCl 1 H2 8 0 moles HCl 3 3 5 moles of Cl2 2 HCl 1 Cl2 7 0 moles HCl 4 Chlorine Cl2 is limiting reactant because it only make 7 0 moles of HCl 5 4 moles of H2 1 Cl2 1 H2 4 0 mole Cl2 1 3 5 moles of Cl2 1 mole H2 1 mole Cl2 3 o mole H2 1 Cl2 limiting reactant What is the maximum mass of sulfur dioxide that can be produced by the reaction of 95 6 g of carbon disulfide with 110 g of oxygen Carbon disulfide reacts with oxygen to form carbon dioxide and sulfur dioxide CS2 3O2 CO2 2SO2 6 How many g of silver bromide can be formed when solutions containing 50 0 g of magnesium bromide and 100 0 g of silver nitrate are mixed together magnesium nitrate is also produced How many g of the excess reactant remain unreacted Percent Yields from Reactions Theoretical yield is calculated by assuming that the reaction goes to completion Determined from the limiting reactant calc Actual yield is the amount of a specified pure product made in a given reaction In the laboratory this is the amount of product that is formed in your beaker after it is purified and dried Percent yield indicates how much of the product is obtained from a reaction actual yield yield 100 theoretical yield 10 A 10 0 g sample of ethanol C2H5OH was boiled with excess acetic acid CH3COOH to produce 14 8 g of ethyl acetate CH3COOC2H5 What is the percent yield CH 3COOH C 2 H 5OH CH 3COOC 2H 5 H 2O 11 Sequential Reactions More than one reaction is required to convert starting materials into the desired products The amount of desired product from each reaction is taken as the starting material for the next reaction Starting with 10 0 g of benzene C6H6 calculate the theoretical yield of nitrobenzene C6H5NO2 and of aniline C6H5NH2 13 Clicker question If 6 7 g of aniline is prepared from 10 0 g of benzene what is the percentage yield Concentration of Solutions Solution is a mixture of two or more substances dissolved in another Solute is the substance present in the smaller amount Solvent is the substance present in the larger amount In aqueous solutions the solvent is water The concentration of a solution defines the amount of solute dissolved in the solvent The amount of sugar in sweet tea can be defined by its concentration 15 One common unit of concentration is mass of solute by mass of solute 100 mass of solution mass of solution mass of solute mass of solvent by mass of solute has the symbol w w 16 What mass of NaOH is required to prepare 250 0 g of solution that is 8 00 w w NaOH 17 Calculate the mass of 8 00 w w NaOH solution that contains 32 0 g of NaOH 18 Calculate the mass of NaOH in 300 0 mL of an 8 00 w w NaOH solution Density is 1 09 g mL 19 What volume of 12 0 w w KOH contains 40 0 g of KOH The density of the solution is 1 11 g mL 20