2LIMITING REACTANTSLIMIT HOW MUCH OF THE PRODUCT CAN ACTUALLY BE PRODUCED DURING THE REACTION
3EXCESS REACTANTSThe reactants that are left over when the reaction stops.*When all the limiting reactant is used up
4How to find the limiting reactants Solve each of the problemsWhich of the problems produces the least amount?This is your Limiting Reactant
5Finding the limiting reactants NaOH + HCl ⇒ H2O + NaCl If there are 25 grams of NaOH, how many grams of H2O will be formed? If there are 16 grams of HCl, how many grams of H2O will be formed? Which is the limiting reactant?______________________
6Finding the limiting reactant 2H2 + O2 ⇒ 2H2O Determine the limiting reactant and how much water will be formed from it, if the following is true: 3 grams of H2 and 5 grams of O2
8Percent Yield Actual Yield x 100 = Percent Yield Theoretical Yield This is a measurement of the accuracy of the chemical reaction.Actual Yield: is the amount of product actually produced, and measured at the end of the reaction.Theoretical Yield: (expected value) is how much product was expected to be produced. This is done by calculating how much should be produced based on the amounts of beginning products.Actual YieldTheoretical Yieldx 100 = Percent Yield
9How to determine the % yield: Complete the conversions of both givensDetermine which substance is the limiting reactantUse the limiting reactant as the theoretical yieldCalculate the percent yieldDivide the actual yield by the theoretical yieldMultiply by 100*This determines how accurate your reaction was in percentage
10Determining the % Yield: Mg(OH)2 + 2NaCl ⇒ 2NaOH + MgCl2Determine the limiting reactant and how many grams of MgCl2 will be formed from it, if there are 4.6 grams of Mg(OH)2 and 7.8 grams of NaCl.What is the % yield if only 5.78g of MgCl2 was collected at the end of the experiment/reaction?
11Determining the % Yield: 2H2 + O2 ⇒ 2H2ODetermine the limiting reactant and how much water should be formed from it, if 3 grams of H2 and 5 grams of O2.3g H2 1 mol H2 2 mols H2O 18g H2O= 27g H2O2g H2 2 mols H mol H2O5g O2 1 mol O2 2 mols H2O g H2O= 5.625g H2O32g O2 1 mol O mol H2OWhat is the percent yield, if the chemist only gathers 3.78g of H2O at the end of the reaction?