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Name:_________________________________ Fizzy Drink Stoichiometry Purpose: The purpose of this lab is for students to develop an understanding of stoichiometry in a real world context. Background Information: The first man-soda non-alcoholic carbonated beverage is attributed to Joseph Priestly. He used chalk (calcium carbonate) and sulfuric acid to produce carbon dioxide with was bubbled into water. Many carbonated beverages have been made since this time. Safety Precautions: Food grade sodium bicarbonate and citric acid are being used. The lab stations have been thoroughly cleaned. For this reason you may eat in lab today. Sodium bicarbonate is slightly toxic is large amounts so limit consumption. Citric acid is a sever eye irritant so safety goggles must be worn. Reaction Scheme: H3C6H5O7 + NaHCO3 Na3C6H5O7 + H2O + CO2 citric acid + baking soda →sodium citrate + water + carbon dioxide Pre-Lab Questions: 1. Write out the balance equation for the reaction scheme. 2. What is the molar mass of citric acid H3C6H5O7? Materials: pre-mixed Kool-Aid, citric acid, baking soda, plastic spoon, paper cups, plastic cups, and a balance Procedure: Part 1: Day One 1. Obtain 3 paper cups and fill each cup approximately ¼ full with Kool-Aid. 2. In your Qualitative Data write down the general characteristics of the Kool-Aid. 3. Taste one of the cups of Kool-Aid. Record your observations in your Qualitative Data 4. Add 0.5 g of citric acid to the second cup of Kool-Aid. Taste and record your observations 5. Add 0.5 g of baking soda to the third cup of Kool-Aid. Taste and record your observations 6. Clean-up your station Part 2: Day One Return to your seat and wait for class discussion to start. In this lab, we want to create a fizzy, good-tasting drink. Brain storm ways to do this to discuss with the class. After the class discussion, complete the following calculations. Show your work in the Calculations section of your notebook and record your results in your Quantitative Data Table. 1. Convert 0.3 grams of citric acid into moles 2. What is the mole ratio of baking soda to citric acid? 3. How many moles of baking soda will react with the number of moles of citric acid you determined in #1? 4. Calculate the molar mass of baking soda. 5. Convert moles of baking soda from #3 to grams. 6. How many grams of citric acid and baking soda do you need to add to your Kool-Aid? Have Part 2 completed before you come back for the second day of lab. Part 3: Day Two 1. Fill a paper cup with Kool-Aid. Pour the Kool-Aid from the paper cup into a larger plastic cup. This is to prevent bubbling over. 2. Now add your calculated amounts of citric acid and baking soda you calculated yesterday. 3. Mix and taste. You may pour your mixture into several smaller cups if everyone wants to try it. 4. Record your observations in your Qualitative Data Table. Data Tables: Quantitative: Citric Acid Baking Soda Molar Mass Moles Grams Qualitative Trial Ingredients Observations Taste 1. ¼ Dixie cupful Kool-Aid® 2. ¼ Dixie cupful of Kool-Aid® + 0 .5 g Citric Acid 3. ¼ Dixie cupful of Kool-Aid® + 0.5 g Baking soda (sodium bicarbonate, NaHCO3) Post-Lab Questions: Complete Sentences! 1. How did your drink turn out? 2. How could you modify your recipe to make it better? 3. If you have 10.0 grams of citric acid how many moles of citric acid do you have? 4. How many moles of carbon dioxide will be produced from the number of moles of citric acid that you determined in 3? (Hint: Use your balanced equation to find the mole ratio) 5. If you have 10.0 grams of baking soda how many moles of baking soda do you have? 6. How many moles of carbon dioxide will be produced from the number of moles of baking soda that you determined in 5? (Hint: Use your balanced equation to find the mole ratio) 7. Refer to your answers for 4 & 6. Which reactant, citric acid or baking soda, produced less CO2?
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