Problem-Based Learning in stoichiometry

Presenters: Sarah Eales, Kevin Cameron, and Christine Wahl

Materials available @ http://chemistrycameron.wikispaces.com/Gwinnett County Public SchoolsPeachtree Ridge High School

Friday

Grand Salon – Marriott

10:00 – 10:50

GPS Addressed

0 SC2 Students will relate how the Law of Conservation of Matter is used to determine chemical composition in compounds and chemical reactions. 0 c. Apply concepts of the mole and Avogadro’s number to

conceptualize and calculate 0Empirical/molecular formulas, 0Mass, moles and molecules relationships, 0Molar volumes of gases.

Classroom Structure

0 This PBL can be utilized in an on level chemistry class as well as an honors/gifted setting.

0 PRHS is on a 90 minute block (4 blocks daily) in which we see our students everyday.

Rocket Launching into a PBL

0 Prior to this activity, the students are involved in an investigational activity which allows them to hypothesize about the appropriate ratio needed to create rocket fuel using zinc and sulfur.

0 This project piggy backs off of that demonstration providing real world application to a very complex concept.

0http://www.periodicvideos.com/videos/mv_zinc_and_sulfur.htm

Partners create a team name

Each student gets a time card

Day 1 - Molar mass

Day 1 of your new job as the quality assurance inspector at the Mendeleev Mechanics Rocket Shop will require that you learn how much every part weighs. And by taking the weight of each of these parts, you can determine how much each of the 7 rockets that we make weighs. At the Mendeleev Mechanics Rocket Shop we measure weight in RPU – Rocket Part Units.

Day 1 - Molar massDetermining the Weight of Rockets

Part Weights: The following table is a list of all of the parts used at the rocket shop with their

respective weight.

Rocket Components: The following is a list of all of the rockets produced at the rocket shop.

For each rocket, the table shows what components make up that rocket.

Number of Each Part Rocket HN SRB LRB W E C Cameron 100 1 1 2 1 1

Eales 200 2 2 4 2 2 Wahl 300 5 1 3 3 3

Kumar 400 12 2 4 4 3 Placek 500 33 1 1 4 4 4

Matthews 1000 34 1 2 5 5 6 Lion 2000 45 2 2 7 6 8

Part Name Abbreviation Weight of One Hex Nut HN 2 RPU Small Rocket Body SRB 115 RPU Large Rocket Body LRB 243 RPU Wing W 119 RPU Engine E 58 RPU Cylinder C 76 RPU

Day 1 - Molar massCalculation of the weight of a single rocket:

Sample Calculation: What is the weight of the Cameron 100 rocket?

Rocket HN SRB LRB W E C Cameron 100 1 1 2 1 1

Part Number Weight Total

Hex Nut (HN) 1 2 RPU 2 RPU SRB (Small rocket body) 1 115 RPU 115 RPU LRB (Large rocket body) 0 243 RPU 0 RPU W (Wing) 2 119 RPU 238 RPU E (Engine) 1 58 RPU 58 RPU C (Cylinder) 1 76 RPU 76 RPU TOTAL WEIGHT = 489 RPU

Day 2 – Percent Composition

Day 2 of your new job as the quality assurance inspector at the Mendeleev Mechanics Rocket Shop will require that you learn what we call the percent composition for each of the rockets that we make. The percent composition is the percent by weight of each part in the rocket. The best way to understand this is to look at two examples.

Day 2 – Percent Composition Calculation of Percent Composition

Steps to Finding Percent Composition 1. Find the weight of the rocket 2. Find the weight of each part 3. Divide the weight of the part by the weight of the rocket 4. Multiply the answer by 100 5. Repeat steps 2-4 for all parts

Sample Calculation: What is the percent composition of the Cameron 100 rocket?

Part Number Weight Total Calculation Percent Hex Nut (HN) 1 2 RPU 2 RPU

100489

2

0.41%

SRB (Small rocket body)

1 115 RPU 115 RPU 100

489

115

23.5%

LRB (Large rocket body)

0 243 RPU 0 RPU 100

489

0

0%

W (Wing) 2 119 RPU 238 RPU 100

489

238

48.7%

E (Engine) 1 58 RPU 58 RPU 100

489

58

11.9%

C (Cylinder) 1 76 RPU 76 RPU 100

489

76

15.5%

TOTAL = 489 RPU 100.01%

Day 3 – Empirical and Molecular Formula

On day 3 as the quality assurance inspector at the Mendeleev Mechanics Rocket Shop there has been a crime committed. An unhappy employee has damaged some of the equipment at the shop by pouring a sugary soda drink all over the assembly line equipment. The suspect has been narrowed down to six employees. Each of the employees drinks a different kind of soda. Each soda contains a different type of sugar in it. All of the sugars in the sodas have carbon, hydrogen and oxygen in their molecular formulas, but all in different amounts. Your job is to analyze each of the six known soda sugars and compare them to the unknown sample taken at the crime scene.

Day 3 – Empirical and Molecular Formula

Procedures:1. For each of the 5 sugar samples, perform the following steps:

a. Mass each of the three elements and record in data table.b. Showing all work, perform calculations to determine empirical formula.c. Showing all work, perform calculations to determine molecular formula.

2. For the unknown, perform the following steps:a. Mass each of the three elements and record in data table.b. Showing all work, perform calculations to determine empirical formula.c. Determine if the unknown matches any of the known sugar samples.

Day 3 – Empirical and Molecular Formula

  Mass of Element Calculated Formula

  Carbon Hydrogen Oxygen Empirical Molecular

Sugar 1          

Sugar 2          

Sugar 3          

Sugar 4          

Sugar 5          

Unknown          

YOUR TURN!

Day 4 – Report

The Strange Case of Mendeleev Mechanics Rocket Shop Vandalism: Case # 1023

 You and Your PRCSI team are called to the scene of a recent vandalism at the Mendeleev Mechanics Rocket Shop. The equipment shows signs of human interference. The one unknown compound found at the scene is C6H15O6. The suspects were found in and around the crime scene and must be identified by the substances found in their belongings or in their persons. Interviews are not available so it is up to you to identify the suspects based on this evidence and the employee database (Sugary drink lab). You must submit your report to your executive director explaining how each suspect was identified. Include a data table showing the suspects, their names, and the formulas and names of the compounds used identify them. As always, the director will want to see all of your work. Based on this data, it is up to you to determine which suspect is responsible for the vandalism and explain their motive.

Day 4 – ReportSuspect with sugar # Analysis of compound1 Na=27.38 H=1.19 C=14.29 O=57.142 C= 44.44 H=6.17 O=49.383 C=40.00 H=6.67 O=53.33

Molecular Mass= 180g/mol4 Ca= 40.00 C= 12.00 O=48.005 C=57.14 H=6.16 N=9.52 O=27.186 C=63.56 H=6.00 N=9.27 O=21.17 The following is a list of the possible compounds:Aspartame C14H18N2O5 artificial sweetenerFlour C6H10O5 used in baking cakesAcetaminophen C8H9NO2 pain killerGlucose C6H12O6 ingredient in chocolateBaking Soda NaHCO3 used in making breadsCalcium Carbonate CaCO3 used in antacids

Day 4 – Report

Here is the suspect list:Christine Chemrules- chemist addicted to sugar-free drinks

Sarah Sugar- manager that eats chocolate for breakfast, lunch, and dinner Kasey Kumar- Astronaut and internationally recognized baker

Cameron Cakes- Chef who is famous for his designer cupcakes

Mechanic Matthews- world renowned mechanic with a shoulder injury

K Tashlein- builder of schools (a very stressful job)

Day 4 – ReportThe Strange Case of Mendeleev Mechanics Rocket Shop Vandalism:

Case # 1023 Report Once all investigative work is finished, you will need to complete a report to be submitted to the courts. The report needs to include the following:

An overview of the process in which you identified all of the victims. (How you determined the substances using empirical formula) Identification of the passenger responsible for the crash. (This is where you make up a motive supported by your evidence)A picture that will help explain the story.  This report should contain at least two paragraphs as well as a colorful picture representing the story. All of this needs to be presented neatly on one or two sheets of paper. Your report must be submitted by ____________________or the suspect goes free!

PowerPoint Presentation

www.chemistrycameron.wikispaces.com

Session Evaluation: Friday

http://tinyurl.com/GSTA27