Name Period Date Ziploc Bag lab Prelab: 1. What instrument is used to measure volume? 2. What instrument is used to measure mass? 3. What is the molar mass of baking soda? Objective: Your objective in this lab is to completely fill a Ziploc bag with CO2 gas. You’ve seen the reaction of vinegar(CH3COOH) and baking soda(NaHCO3). This reaction produces CO2 by the balanced equation below. CH3COOH(aq) + NaHCO3(s) à CH3COONa(aq) + H2O(l) + CO2(g) You must first determine the maximum volume of the Ziploc bag. In the end, this volume will be filled with CO2(g). Using stoichiometry you can calculate the mass in grams of baking soda you will need. Because the vinegar is diluted, you will need to use the molarity to calculate the volume of vinegar needed to completely react with all the baking soda. Finally you will measure out those amounts and mix them in a Ziploc bag. Materials: o Ziploc bag o 100mL Graduated cylinder o balance o Vinegar o Baking soda Procedure: 1. Obtain a Ziploc bag. 2. Determine the volume of the bag by filling it with water, then pouring the water into a graduated cylinder. Record this volume(in liters) in the data section. 3. Measure the temperature and air pressure of the room. Record these in the data section. Be sure to change the pressure and temperature to atm and Kelvin. 4. Using the volume of the bag, calculate how many moles of CO2 you would need to completely fill the bag. Record this value in the data section. 5. Calculate the amount(g) of baking soda needed to produce the correct volume of CO2. Record this in the data section. 6. Calculate the moles of vinegar needed to produce the correct volume of CO2. Record this in the data section. 7. Calculate the volume of vinegar you will need. Using the molarity of the vinegar and the number of moles you need was calculated in step 6, calculate the volume of vinegar you need. Record this in the data section
8. Measure the amount of baking soda needed and put it in the corner of the bag as shown by your instructor. Twist the bag to isolate the baking soda. 9. Do the next step near a sink. 10. Measure the amount of vinegar needed and pour it into the bag. Seal the bag and mix the two reactants. Record your observations. You may need to agitate the bag to help the reaction. 11. After the reaction is complete, open the bag and use a piece of pH paper to test the pH level of your products. Estimate the pH and record it. Data/Calculations: Molarity of commercial vinegar 0.83 M Volume of the bag mL =______L Air Pressure mmHg = Temperature
°C = _______K Moles of CO2 needed moles Calculate the amount of NaHCO3 g Moles of CH3COOH moles Calculate the amount of vinegar L = ______mL Estimated pH level Observations: Questions: 1. Did you reach a 100% yield? How would you know?
atm 2. What errors could have caused your bag to burst or not completely inflate? 3. How many grams of H2O were produced? 4. How many grams of CH3COONa were produced? 5. Do you think it is reasonable to ignore the volume of H2O and CH3COONa created in this reaction?