1. Chapter 4:ReactionStoichiometryMole / MassrelationshipsIn this video, you will learn to:Determine the mass of a reactant or productgiven the mass of another reactant orproduct in the reactionCalculate theoretical yield and use it to findthe percent yield based upon experimentalresultsIdentify the limiting reagent in a problem anduse this knowledge to calculate thetheoretical yield of a product

2. Determining Mass Relationships in Reactions How many grams of water are expected to beproduced in the combustion of 1.00 g ofglucose? 3. Stop and Practice Pause this video for a minute and use the same sequence of steps to:1. Find the mass of carbon dioxide which would result from the combustion of 1.0 g of glucose2. Find the mass of oxygen which would be required to exactly react 1.0 g of glucoseGo on Aspen, open the Video quiz, and recordyour answers for questions 1 and 2. 4. Percent Yield 5. Stop and Practice Pause the video again and use the formula provided to:1. Find the percent yield of water for a laboratory experiment in which 0.47 g of water were formed from 1.0 g. of glucose.Go on Aspen, open the Video quiz, and recordyour answer to question 3. 6. Limiting Reagentshttp://wps.prenhall.com/wps/media/objects/602/617005/LimitingReactantActivity.html Go to the link provided and select a reaction. (You can change the reaction typeif desired using the drop down menu). Select the amount of one reactant which you will use by clicking on the bulletnext to the desired quantity. Leave the graph type on dot Click Add Reactant 1 and view the mass added and the mass of productsformed. Continue clicking Add Reactant 1 and view the graph that forms. Start a new experiment, change the amount of other reactant, and click AddReactant 1 again to make a new graph. Repeat with other reactions. 7. Stop and ThinkPause the video and explainyour observations: Why did the graph level off to show that noadditional product resulted even though youcontinued to increase the amount of reactant1 used?Go on Aspen, open the Video quiz, and recordyour answer to question 4. 8. Limiting Reagents Why is one reagent used in excess?If one reactant is used in excess, you can be certainthat the other reactant is fully consumed in thereaction and is therefore the limiting reagent. The limiting reagent is used to determine:The theoretical yield of product which should beformed 9. Class Forum Question Go to our class forum on Aspen (Open the APChemistry Class Page) and post your answer tothe following question:How does a chemist decide which reactantshould be used in excess and which reactantshould be the limiting reagent when she sets upan experiment? (There are many good answers tothis question Read and respond to yourclassmates ideas.) 10. 3.50 g of Na3PO4 is mixed with 6.40 g of Ba(NO3)2. Which isthe excess reagent?Step 4: Is the experimental ratio too high or too low?Theoretical ratio is 0.67Experimental ratio is 0.869The experimental ratio is too high. That means thenumerator is too large and therefore the Na3PO4 is in excess;the Ba(NO3)2 limits.Think about the meaning of a fractionA larger decimal is theresult of a large numerator and small denominator. A smallerdecimal is the result of a larger denominator and a smallernumerator. 11. Putting this to practical use: What is the mass of Na3PO4 which is excess?Hints: Given the mass of Ba(NO3)2 which will beconsumed, how much Na3PO4 will be used?How much will be left over?Use the problem solving steps on slide 4! How many grams of Ba3(PO4)2 can be formed?Hint: ALWAYS use the limiting reagent mass todetermine the mass of the product formed. 12. Checking Your Work! 13. On your own In the reaction between SiCl4 and Mg to produceMgCl2 and Si, if you begin with 225 g of eachreactant, which is the limiting reactant?(aspen, question 5)How much extra, in grams, of the excess reagentdo you have?(aspen, question 6)What quantity of Si, in grams, can be formed?(aspen, question 7) 14. Adipic acid (H2C6H8O4) is a material used for theproduction of nylon. It is made commerciallyby a reaction between cyclohexane, C6H12, andO2: 2C6H12 + 5O2 2H2C6H8O4If you carry out this reaction with 25.0 g ofC6H12 and it is the limiting reactant, what is thetheoretical yield of adipic acid?(aspen, question 8) 15. If you obtain 33.5 g of adipic acid from the reaction, what is the percent yield?(aspen, question 9)Youre almost done!!! 16. Getting Ready for Next Class - Whoosh Bottle DemonstrationCombustion of isopropyl alcoholWhat is the theoretical yield of water?What volume of oxygen is required to completely combust 20 mL of alcohol?