Gas Law Stoichiometry Project: Students will build knowledge of gas laws through lab investigations and experimental design. This project includes 2 in class guided experiments and an engineering project with scheduled launch during class.

Quizzes: Throughout the project, students will take mastery quizzes to ensure they are learning and understanding the material. All group members must pass the quiz in order to move on to the next section. If not all the group members pass the quiz, the entire group will do a remediation activity, correct their quizzes, and requiz before moving on.

Grading: The project is designed to be hands on learning and self-paced to allow students to work with the content and grasp a full understanding of gas laws. The amount of work expected from students will resemble that of a unit test. Students will work with peers in groups no larger than 3 people and are expected to contribute equally to the project. Groups will peer evaluate the work and effort put in by each member for 25% of their grades. Students will complete individual guided practice through the project to review and ensure mastery of exam objectives. This will count for 25% of their grade. Students will create a lab portfolio over their findings and engineering project that will include pre-labs, lab data, analysis of data, and post lab information. The lab portfolio will count for 50% of their grade. Late projects will be accepted for a maximum grade of a 70% for 2 blocks after the due date.

Exam Objectives: Learn, understand, and master the ideas of gas laws through investigations and engineering. Students should have a full understand of

□ Gas at Standard Temperature and Pressure□ Converting units (atm, torr, °C, K) □ 22.4 L= 1 mol of gas at STP□ PV=nRT

□ Gram to gram stoichiometry □ Single replacement reactions□ Double replacement reactions

going into the last exam of the six weeks. There will be guided practice at the beginning of every class so students can check in with their mastery. There will be an exit ticket once a week to check the progress of student projects. A test review will be given for the exam.

Project Timeline:A Block B Block Task Completion

4/26 4/27 Guided Practice: gas law intro, PV/T, STP, converting units atm, torr, K, °CProject time: choose teams, find volume of Ziploc bag.Homework: read over project intro & complete pre-lab for Part I

5/1 4/28 Guided Practice: Introduce 22.4 L =1 mol, work conversions problemsProject Time: complete calculations, complete airbag labHomework: post-lab part I

5/3 5/2 Guided Practice: PV=nRT module lesson, work conversion problemsProject Time: pre-lab part II

5/5 5/4 Quiz Part I when student is readyGuided Practice: review PV=nRT, mixed problemsProject Time: pop rockets lab, work on post labHomework: part II post-lab, part III pre-lab

5/8 5/9 Quiz Part II when student is readyGuided Practice: SR Rxn notes, SR rxn practice with mixed stoichProject Time: Part III engineering build

5/10 5/11 Guided Practice: SR Rxn practice & SR LabProject Time: Part III rocket launch, work on portfolio

5/15 5/12 Quiz SR Rxn & mixed stoichProject Time: wrap up lab analysis and work on portfolios (due next class)

Peer Evaluations Sheet: 25% of grade *Half grades are okay!Topic 1 2 3

Participation in Lab

Peer did not help in lab and was absent multiple days. Peer sat and did nothing most of the time.

Peer was helpful in lab, getting supplies, and discussing topics. Peer was helpful in analysis or conclusions.

Peer was active in lab, helping answer questions, prep labs, and do lab analysis.

Engineering Project

Peer was not active in creating rocket. Peer only helped during class time when prompted.

Peer was active in creating rocket and had good ideas and concerns. Peer helped build rocket or supply items.

Peer went above and beyond when creating rocket. Peer had ideas and contributed significantly to the build.

Lab Analysis Peer did not help in the lab analysis or calculations. Peer had limited contributions.

Peer was active in lab analysis, calculations, and writing portfolio.

Peer was active and took initiative in lab analysis and calculations

Lab Portfolio Peer was not active in writing portfolio or helping create the visual. Peer had limited contributions.

Peer was active in writing portfolio and helped create/build the visual.

Peer was active in writing portfolio and took initiative creating/ building the visual

Partner: __________________________________Topic Score Justification

Participation in Lab

Engineering Project

Lab Analysis

Lab Portfolio

Total Score /12

Partner: __________________________________Topic Score Justification

Participation in Lab

Engineering Project

Lab Analysis

Lab Portfolio

Total Score /12

Partner: __________________________________Topic Score Justification

Participation in Lab

Engineering Project

Lab Analysis

Lab Portfolio

Total Score /12

Partner 1: ___________________ Partner 2___________________ Partner 3___________________

Lab Portfolio: 50% of gradeTopic Check List Score Comments

Cover Page5 points

□ Title of project□ Name of group members□ Class period□ Subject, year

Summary Page10 points

□ Purpose of lab□ 22.4 L = 1 mol explanation□ PV=nRT explanation

Airbag15 points

□ summary of lab results□ pre-lab □ data table□ lab calculations□ post lab

/

Pop Rockets15 points

□ Experimental question□ hypothesis□ pre-lab□ lab results and data□ post-lab □ Short summary of lab

/

Engineering50 points

□ less than 3 pages□ Title□ Abstract summary□ Background research□ Materials list□ Simple procedure□ Rocket Sketch □ Results and data□ Calculations□ Post lab calculations□ Conclusion

/

Engineering Design & Build

3 points

□ Rocket doesn’t exceed 46cm□ Rocket launch in class□ Rocket made 720cm height.

/

Organization2 points

□ Portfolio is the order outline□ Looks professional□ Is bound together well

/

Total Score

GAS LAW STOICHIOMETRY

Air Bag Background InformationChemists can use concepts like stoichiometry, molar mass, and balanced chemical equations to predict just about anything about a chemical reaction. The invention of the automobile air bag, for instance required consideration of not only the chemistry, but economic and environmental factors.  The automobile air bag is a remarkable device. It is simple in concept, but the design requirements of the system are actually very demanding.  When a crash occurs, an air bag must inflate rapidly (within about 40 milliseconds), cushioning the occupants against impact.  The gas produced must be nontoxic, odorless, and cool enough to avoid burning the occupants. You’d also like the compounds used to be stable, and nontoxic; so they don’t expand unexpectedly and are easy and safe to dispose of and don’t create hazards in a land fill or junk yard. Sodium azide (NaN3) is a stable solid and a small pellet can easily be stored in air bag compartments. A huge volume of nitrogen (N2) gas is produced rapidly and is nontoxic and relatively cool. Sodium azide itself, however, is pretty nasty. Toxic chemicals like sodium azide are a major concern in landfills where undeployed air bags are discarded. These issues, as well as the quest for better and cheaper systems, keeps open the search for other compounds and formulations for the gas-producing reaction used in the system.

Scenario objective: In this experiment, you have been asked by your boss, Iam Gaseous, of the AIR BAGS R US Co. to investigate the design of a small-scale airbag system as a child safety device to put in baby carriages. Your model airbag should expand to the largest possible volume without breaking the seal on the bag. To simulate the airbag we will use a zip lock bag. To simulate the human head we will drop an egg onto the airbags you create to check their efficiency. Because of sodium azide’s toxicity, Mr. Gaseous suggests you use look into other reactions to test your engineering design.

Standard Temperature and PressureIt was defined by the IUPAC as conditions at 273.15 K and 1 atm. Standard volume for a mole of gas at STP conditions is 22.4 L. This means for any ideal gas at 273.15 K and 1 atm of pressure, a single mole will fill a volume of 22.4 liters. This is a useful conversion for gas production and volume determination. *Technically we are not at standard temperature, but the error is less than 5% so we will assume STP

The MoleThe mole is a quantity of measurement used by chemists for amounts of chemicals in a reaction. A mole now has 4 conversion factors you should know.1 mol = molar mass of the chemical 1 mole = avagadro’s number of particles1 mol of gas = 22.4 L of gas at STP Molar Ratio from balanced chemical equations

Stoichiometry is the study of chemical quantities. We use stoichiometry to investigate the relative amounts of reactants and products. When investigating these relationships, don’t forget the golden rule of stoichiometry- all quantitative relationships in chemistry are based on the mole! When comparing amounts of reactants and products, we don’t talk about grams, liters, or molecules… we always compare molar amounts.

Based on experiments developed by Jim Klent and Angelica Stacy (ChemConnections)

PART ONE: AIRBAG INFLATION: Design an experiment to keep a baby egg from falling to its’ death.

Pre-Lab:

1. Obtain an “airbag”. This is your only airbag for the lab so don’t poke holes or break it! What things do you need to determine regarding the bag? How might you figure those things out?

2. Use your ideas above to determine physical properties of the bag. List them below with your measurements including units!

3. Why can we not use sodium azide for our reaction to fill the bag?

4. Write the balanced chemical equation for acetic acid and sodium bicarbonate. (Hint: H2CO3 will rapidly break down into H2O and CO2 as products)

5. What product of the reaction will fill the bag up? ____________________________.

Lab Calculations: 6. How many liters of gaseous product should you produce to fill the bag? _________________________

Remember we want just enough gas to create a cushion without breaking the seal on the bag.

7. Determine how many grams of sodium bicarbonate you need to react to produce the volume of gaseous product in #6. Assume we’re at STP.

Assign the roles as follows below. Dummy Provider- provideds crash test dummys- bring 2 eggs next class ____________________________________

Crash Test Initiator- responsible for initiating the crash and inflating airbag. ________________________________

Emergency Response Team- will tend to crash test dummy and clean up. __________________________________________

8. We want all of the sodium bicarbonate to react. Use your mass determined in #7 to calculate how many grams of acetic acid you need to react.

9. The density of acetic acid is 1.05 grams in 1 mL (1.05g/mL). Determine the volume of acetic acid.

10. We will be using vinegar as our acetic acid source. Vinegar contains 5% acetic acid. How much vinegar should you use? (Hint: Answer from #10 is only 5% of the total volume you need)

11. Before proceding to lab have your teacher grade you pre-lab work. Teacher approval ________________

Build: It’s time to create your airbag! You will have a bag, vinegar, NaHCO3, scale, graduated cylinder.

12. In order to have the bag inflate properly, much like car airbags, the chemical reaction can only be activated when triggered. Brainstorm ideas below to keep the reaction from occuring until you are ready for the bag to inflate.

13. Pick your best idea above. You will have 1 trail run to fill your airbag. Take notes of what does and does not work so you can make adjustments.

Crash Test Trails: You get 2 crash test dummy trials, but may not alter the air produced in the bag between trails. Trail Observations Things to correct/adjust Results

1

2

Post Lab Questions: Applying Gas Stoichiometry 14. Based on your lab data, if 2.01 g of NaHCO3 is used with excess vinegar will you produce too much, just

enough, or too little gas to fill the sandwich bag with gas. Justify your answer with calculations.

15. Write the balanced chemical reaction for an alternate reaction of hydrochloric acid and magnesium metal.

16. Use the volume of the bag to calculate the mL of 6.0M HCl needed to fill the bag.

Socrative Online Homework #1 : Each person will need to complete the online socrative over gas laws to prepare for the quiz. Room name is Bowiechem.

Gas Law Stoich Basics Quiz: Before starting part II you will take a quiz on part I. Each person will take the quiz individually in class. When you are ready to take the quiz ask your teacher. You must all pass the quiz to move on to part II.

PART II: Pop Rocket Gas Law StoichiometryYou now have an understanding of how a reaction can produce a gas and how we can determine the amount of reactant needed to produce enough gas. We will utilize this information for part 2. We will start with microscale rockets before you will take on the engineering goal of building your own rocket.

Background: “How does a spacecraft lift off and get into space? The simple answer is that it has rocket engines that propel it. The rockets depend on combustion to provide the thrust the spacecraft needs to overcome the force of gravity and climb into orbit. Combustion is a fast, exothermic chemical reaction between a fuel and an oxidizer (such as oxygen) in which the fuel burns and heat is produced. During the chemical reaction, new compounds are made. These are referred to as the exhaust. The rockets push the hot exhaust out from the bottom at high pressure and thus the spacecraft is thrust upward. In this activity instead of using rocket fuel you will use sodium bicarbonate and acetic acid to make a different kind of chemical reaction that can launch a small-scale rocket made from a film canister. You'll take advantage of the pressure the carbon dioxide gas makes in the capped film canister to launch your rocket.” https://www.scientificamerican.com/article/bring-science-home-homemade-rockets/

Pressure of a gas can be calculated from the equation PV=nRT. P is the pressure in atm, V is volume in L, n

is the number of moles of gas, R is a constant 0.0821L atmmol K , and T is the temperature in Kelvin. You must

be given 3 of the 4 variables in order to properly solve this equation. Watch this video for an explanation. https://youtu.be/WhP6zJbSxec

EXAMPLE: A 25 mL film canister needs to produce a pressure of 3.4 atm to launch at a temperature of 28°C. Calculate the number of moles of gas needed to launch the canister. 1. Write out your givens. P=3.4 atm V= 25mL= 0.025 L n= ? T= 28°C = 298.15 K

2. Plug into the equation 3.4 atm (0.025 L )=n(0.0821 L atmmol K )(298.15 K)

3. Rearrange and solve for variable.

n=3.4 atm (0.025 L )

(0.0821 L atmmol K )(298.15 K)

=0.085 L atm mol K24.48 L atm K

=0.0035 mol of gas

Watch this video for another example on how to cancel units and solve PV=nRT. https://youtu.be/TqLlfHBFY08 Background Questions:

1. How many moles of oxygen will occupy a volume of 2.5 liters at 1.2 atm and 25°C?

2. What volume will 2.0 moles of nitrogen occupy at 720 torr and 20.0°C?

3. What pressure will be exerted by 25 g of CO2 at a temperature of 25°C and a volume of 500.0 mL?

4. What temperature will 5.00 g of Cl2 exert a pressure of 900.0 torr at a volumne of 750.0 mL?

Answers: 1) 0.122 mol O2 2) 50.8 L N2 3) 28 atm 4. 153 K

Pop Rocket Lab: We will assume the gas produced is ideal so you may use the ideal gas law. Experimental Question: How does the pressure produced from the reaction affect the launch height of a rocket?

Hypothesis: Write a hypothesis to the experimental question based on the information from the Airbag Lab and your module I & II calculations. (Hint: What amount of sodium bicarbonate would you need to react with 15 mL of vinegar to launch the highest rocket?)

Pre-Lab Questions: 1. You will be using solid sodium bicarbonate and acetic acid as your rocket fuel. Write the reaction below.

2. You will be using a 15 mL portion of vinegar, which is a 5% acetic acid solution by volume. The density of vinegar is 1.05 g/cm3. Calculate the moles of acetic acid in one portion of vinegar.

3. What is the maximum amount of sodium bicarbonate that will react with 15 mL of vinegar?

Procedure: Before you start the lab collect some data on the experimental surroundings. Record that data in Table 1.

Data Table 1: Experimental SurroundingsLaunch temperature

Height of canister

Diameter of canister

Be sure to record any other conditions or surrounding information you may need.

Trial I: 1. Obtain a film canister + lid, a launch pad, and a yard stick. Please work responsibly outside of the room.2. Adding the baking soda directly to the vinegar will not give you enough time to place the cap on the

film canister. Design a mechanism that will allow you to place the lid on the canister, turn it upside down, and then set it down on the launch pad before the reaction begins.

3. Use exactly 0.50 grams of sodium bicarbonate in your first trial.4. Measure exactly 15.0 mL of vinegar using a graduated cylinder and add it to your film canister. 5. Introduce the sodium bicarbonate to the acetic acid based on your design in #26. Have one lab partner watch the ruler while the other adds the sodium bicarbonate to the canister, snaps

on the lid tightly, and places it upside down on the launch pad. STAND BACK and record the max height of the rocket.

Trial II: 7. Rinse and dry film canister. Repeat steps 3-6 with 1.00 g sodium bicarbonate.

Think About It! How does changing the amount of baking soda effect the height of the rocket after launch?

What is the perfect amount of baking soda to launch the rocket to a maximum height and react all of the vinegar?

Trail III: 8. Rinse and dry film canister. Repeat steps 3-6. Choose a mass of sodium bicarbonate under 5.0 g while

keeping the volume of vinegar constant. Data Table 2: Experimental Data

Actual mass of NaHCO3 (g) Volume of Vinegar (mL) Max Height (cm)15

15

15

Post Lab: Data Analysis:Use your max height trial to answer questions 1-3. 1. Determine the volume of the film canister you used from the volume of a cylinder equation: V=π r2 h

2. Determine the moles of sodium bicarbonate used in the trial that gave you the max height of launch.

3. Using the temperature from launch day, determine the pressure of gas that was created from you max rocket launch.

4. If a rocket used 5.46 g of sodium bicarbonate, how much vinegar would need to be added so that all of the sodium bicarbonate reacts? Show your work.

5. How much pressure would your rocket have produced from the 5.46 g of sodium bicarbonate at a temperature of 27.6°C in your film canister?

Conclusion: Write a conclusion to this lab based on your hypothesis. Conclusions should give a summary of your lab data and what information you learned. Include possible sources of error and how you would correct them. Human error and math calculations are not considered errors.

Socrative Online Homework #2: Each person will need to complete the online socrative over gas laws to prepare for the quiz. Room name is Bowiechem. Gas Law PV=nRT Quiz: Before starting part III you will take a quiz on part II. Each person will take the quiz individually in class. When you are ready to take the quiz ask your teacher. You must all pass the quiz to move on to part III.

PART III: Engineer a Rocket with Gas Law StoichiometryYou will now build your own rocket. There are a few stipulations for building rockets. All rockets must be legal and propelled only by gas pressure (no explosives or combustions). You can only use supplies found at home and chemicals that are in household products. You may request chemicals from the teacher that are found in the supply closet at school. Chemical requests need to be made a block in advance- don’t assume we have everything.

Part I: Chemical Design 1. Make a list of chemicals you could use that are household products. Include their chemical formulas.

2. In order to make the rocket propel, you need to create pressure from a gaseous product. Common gasses produced in chemistry are carbon dioxide CO2 , hydrogen gas H2, ammonia NH3, nitrogen N2, oxygen O2, hydrogen sulfide H2S, dinitrogen oxide N2O, sulfur dioxide SO2, among others.

Think about what chemical reactions you could create from your list of household products. Write 3 balanced chemical equations that could produce a gas. -

-

-

3. Collaborate with your team. Research the products of your chosen reaction. Write that reaction with proper state signifiers that you choose to propel your rocket.

4. Find the MSDS sheet for both reactants online and print off the hazards, toxicity, storage, and disposal information for each chemical you will use.

Part II: Trial Run5. You will do a mini-scale rocket launch using a film canister. Calculate how much of each reactant you

need to produce enough gaseous product to launch the film canister. (Hint: use your data from Pop Rockets Lab to determine volume of gas needed.)

6. Write your observations down along with any measurements you make.

Part III: Physical Design 7. Reflect on your Pop Rockets Lab. What are some physical traits you want in your rocket?

8. Building rockets or unmanned aircraft systems (UAS) is strictly regulated by the Federal Aviation Administration. Visit the following link and look up regulations for your rocket: https://www.faa.gov/uas/getting_started/Max weight: ________ Max flying height: ________ Not within _____ miles of an airport.**Your engineered rocket cannot exceed 46 cm in height.

9. The rocket will be propelled only by the pressure from the gas you create (not combustion). Therefore, weight of your rocket is important. What materials would you want to use to build your rocket? Create a materials list.

10. Sketch a design of your rocket and label the materials.

11. Build your rocket as a team. Begin by building the part that will hold the chemical reaction. You will want to be able to easily access this “canister” or adjust it as you build. Your rocket body should be detachable to the canister. Be sure to include a proportional sketch of your final rocket with labeled materials in your lab portfolio.

Part IV: Calculation Analysis12. You need to determine the volume of gas you must produce to fill your “canister”. Write down the

volume equation for the canister shape you are using.

13. Calculate the volume the gas that will occupy your canister.

14. How many moles of gas do you need to produce to fill the canister assuming STP conditions?

15. Assuming room temperature of 25°C, what pressure will the gas produce in the canister based on the volume you calculated in #13 and the moles in #14.

16. The pressure of gas calculated is the amount needed to fill the reaction canister. That does not guarantee it will propel the weight of the rocket. In order for a rocket to launch it needs thrust, pressure that overcomes gravity and the weight of the rocket. We will calculate the amount of pressure needed to propel your rocket now.

Once your rocket is built, find the weight of your empty rocket in kilograms: __________________.

17. Calculate the area for the base of your rocket. If you have fins you will calculate the circular are under the outside of the fins like the picture to the right. Show your work.

18. Convert your base area to meters squared (m3). Hint: convert your lengths in to meters and recalculate or convert from cm3 to m3 (1003 cm3 = 1 m3).

19.Calculate the minimum pressure your rocket needs to propel off the ground and reach a height of 720 cm.

Use the equation: P=mghA where P is pressure, m is mass in kg, g is the gravitational constant 9.8 m/s2, h

is height in meters, and A is area in m3. P=¿

kgm s2

20. The pressure you calculated above is in Pascals. Convert the pressure in #19 to atm.

21. This is the minimum amount of pressure you need to launch your rocket a height of 720 cm based on its current weight. Compare this pressure to the pressure that will be produced from your canister in #15.

22. What adjustments should you make to your rocket? If you decide to change the reaction canister you will need to recalculate #12-20 with your new volume and weight.

23. Determine how much pressure you would like to produce to ensure your rocket goes 720 cm.

24. Use that pressure in atm to calculate how many moles, n, of gas product you need to produce using the volume of your reaction canister and room temperature of 25°C.

25. Use the moles of gas in #15 to calculate how many grams of solid product you need to react.

26. Calculate the amount in grams of other reactant you need from your answer above. (You may need to look up the density of the chemical in g/mL if it is a aqueous reactant)

27. Make sure that your canister can hold this volume of reactants.

28. Using your amount of solid product in #23, how many mL of gas will you produce?

If you make adjustments to your rocket along the way be sure those are reflected in your calculations and sketches for your portfolio.

Part V: Rocket LaunchRocket launch will happen in class on the scheduled days. If you decide to do practice launches outside of class that data cannot be used. If you break your rocket doing practice launches you will need to fix it before launch day. Launch day will only happen that day in class. If you miss launch day there are no make-ups so plan accordingly. Launch day is the last half of class on 5/10 & 5/11.

Post Lab: Engineer a Rocket1. Based on your measurements in Data Table 3, what was the exact pressure of gas you produced from

your rocket?

2. What changes could you have made to launch your rocket higher?

Conclusion: Write a short summary of your results and conclusions based upon the performance of your rocket. Include sources of error (human error or wrong math is not an error) and ways to correct it.

Data Table 3: Experimental DataMass (g) of Reactant 1

Volume (mL) of Reactant 2

Max Height (cm) of rocket

Temperature at Launch

PART IV: Gas Law Stoichiometry Lab Portfolio You and your team will put together a portfolio of your project. Portfolios should look professional and keep all of your project data together.

You should include the following things you your portfolio in this order: Cover Page: Title of your project, names of all group members, class period, subject and year.

Summary Page: A written page of the purpose of the project. Should outline what you learned and the concepts you mastered in each section of the project.

Airbag Lab: Short summary of the lab and results. Include your lab calculations with the pre-lab grade.

Pop Rocket Lab: Experimental question, hypothesis, short conclusion of the lab and results. Include your lab calculations.

Engineering Lab: Full lab write up as outlined below. Not to exceed 3 pages. TitleAbstract- a summary of the purpose of the lab, content learned, results, and place for error (max 6 sentences)Background information- research on chemical reaction and science behind rocket launch. Explain equations

used in your calculation sectionMaterials list and summarized procedure- include your rocket build and sketch hereResults & Analysis- Short explanation of your results. Include your lab calculations and post lab calculationsConclusions- Written conclusion summarizing results and rocket performance including sources of error and

changes you would make.

Peer Evaluation Sheets

Portfolio grading sheet