Materials • Balance • Weighing Paper • 1 teaspoon of Baking Soda • 1 small bottle of vinegar • 1 zip lock plastic bag • Very large beaker of water
Procedure • Fold weighing paper. Mass it on balance. • Put one teaspoon of baking soda in the weighing paper. Mass it. • Subtract the two values to find the mass of the baking soda. • Fill the small bottle with vinegar, cap. • Put baking soda and vinegar bottle in plastic bag. • Empty bag of as much air as possible, seal shut, mass on balance. • Estimate the amount of volume of bag.
Procedure Continued • With Bag sealed, open bottle of vinegar. • Re-mass the bag. Account for any difference in mass from beginning to end. • Use large beaker with water to estimate the new volume of the bag. • Clean up bottle for next class to use. • Throw away plastic bag. • Make sure equation is balanced. • Figure out what volume of gas was supposed to have been produced using stoichiometry
Observations • Mass of weighing paper ___ • Mass of baking soda plus paper ___ • Mass of baking soda ___ • Volume of bag before vinegar was opened ___ • Mass of bag before opening vinegar ___ • Mass of bag after opening vinegar ___ • Volume of bag after vinegar opened ___ • Estimated volume of gas produced ___ • Balanced equation for reaction____ • Full stoichiometry problem for figuring volume of gas.____
Equation ___NaHCO3(s) + ___CH3COOH(l) ___CH3COONa(aq) + ___H2O(l) + ___CO2(g)
Use Stoichiometry to find liters of gas from grams of baking soda. • Find the molecular weight of NaHCO3 • Use atomic weights: • Na = _____ • H = _____ • C = _____ • O__x3 = ____ • Molecular weight of baking soda is ___g/mol
The Stoichiometry Math ____ g NaHCO3 x 1 mol NaHCO3 _____ g NaHCO3 ___ mol CO2 x 22.4 liters = ___mol NaHCO3 1 mol any gas = ____ liters of CO2 gas
Questions • Give two reasons why it is difficult to get an accurate reading of the volume of the plastic bag before and after. • Give some reasons why you didn’t get the volume of CO2 gas that you expected from the stoichiometry math.
Questions II • Why should the weight, before and after the vinegar bottle is opened, be the same? • Give a reason why the mass might have changed, even though it shouldn’t. • Give two reasons why might this baking soda reaction might be good to use in your sinks monthly to keep your home plumbing from clogging up?
Extra • What are some ways to improve this experiment? • What are some additional questions that could be asked for this experiment?