Design an Air Bag Balanced equation: NaHCO3(s) + CH3COOH(aq) → (sodium bicarbonate) + (acetic acid) CO2(g) + NaCH3CO2(aq) + H2O(l) → (carbon dioxide) + (sodium acetate) + (water) Balanced equation tells us the ratio of reactants to maximize the product. Example: 1 mole NaHCO3(s) and 1 mole CH3COOH will produce 1 mole of CO2(g) Controlling the outcome (=products) 1. Calculate the number of moles provided a given amount (mass) of sodium bicarbonate Example: 2 grams of NaHCO3 moles = 2 g x 1mole = 0.0238 moles 84.01g therefore 0.0238 moles of CH3COOH are needed to maximize the amount of CO2 produced from 2 grams of sodium bicarbonate. 2. Calculate the volume of acetic acid Important information: 1:1 ratio of sodium bicarbonate to acetic acid 1 mole of CH3COOH 60.06g 60.06mL Example: 0.0238 moles CH3COOH x 60.06 g/mole = 1.43g CH3COOH = 1.43mL CH3COOH Challenge: Create your own “air bag.” Each set of lab partners will be competing with the other teams to produce the most effective and scientifically valid air bag. You are trying to maximize the yield of CO2 produced through the reaction with minimal mass. Keep in mind the following guidelines: Generate a lot of CO2 gas without bursting open the bag that contains the gas. Keep the mass of your overall apparatus down…airbags in cars can’t weigh a lot or you would lose gas mileage! Essentially, minimize the mass of everything you use while still fully inflating your air bag. You should complete the table below with accurate numbers. At the end of the lab, your group will present your best model of an airbag to the class. It will be deployed, weighed and then measured for its volume. You have approximately 30 minutes to complete your test runs and determine your procedure. Here are some hints/reminders: 1. Create a data table to help organize your information for each trial: mass sodium bicarbonate, volume acid, experimentally measured volume of bag. 2. You may use any of the materials and equipment found in the lab to achieve your goals. 3. You are NOT limited to 2.0 g of baking soda in each trial. The calculations above were only an example mass used for the explanation. 4. Try to determine what a “good” mass (the mass of things that make the bag big) and what is “bad” mass (mass that is a part of the system, but doesn’t contribute to the goal). How can you maximize the good mass and minimize the bad? 5. You are not limited to 1 trial during the practice time! Your team should develop a plan and carefully record results in the table to summarize your experiment. Top Performing Air Bag Question Show work! Answer a. Mass of NaHCO3 (g) a. b. Moles of NaHCO3 b. c. Volume CH3COOH (mL) c. d. Moles of CH3COOH d. e. Mass of entire bag (g) To be completed after presentation to class. f. Volume of bag (mL) g. Mass : Volume (g/mL) To be completed after presentation to class. e. f. i.