Experiment
Post Lab: Plop, Plop, Fizz, Fizz: The Mass Percent of NaHCO3
Procedures:
1.) Weigh 100 ml empty beaker, clean it and dry it. Write down the weight in the lab notebook to the closest 0.001g
2.) Get a graduated cylinder and place 35 ml of de-ionized distilled (DI) water in the weighted 100 ml beaker.
3.) Get the beaker and make sure it's clean and re-weight it including the water and then recorded it. (Clean the beaker with Kim wipes every time before weighing it)
4.) Break Alka-Seltzer tablet into two halves and weight each half carefully.
5.) Add one half of the tablets to the beaker that contains the distilled water. Then add the pre weighted watch glass on top of it in an inverted position to deflect any splatter. Mix the contents and make sure it dissolves completely in the solution.
6.) When the reaction finished and the bubbles disappear weigh all of the materials again separately (Beaker, solution and the watch glass). Record the new masses
7.) Empty the content of the beaker in the appropriate sink and clean it with distilled water. In the end make sure to dry the beaker and the watch glass using Kim wipes and paper towels.
8.) Again using a graduated cylinder, place a 5 ml of vinegar in the 100 ml beaker. Then pour water into the cylinder until it reaches 35 mL. Place the solution into the weighted beaker used at the beginning of the experiment.
9.) You must reweigh the beaker including the solution and make sure the beaker is clean and dry. Make sure you record the weigh
10.)Now add the 2nd half of the tablet to the beaker including the distilled water and cover it with the watch glass. Make sure you mix the solution until the tablet completely dissolves in the solution
11.) When the reaction is complete reweight the beaker, the solution, watch glass and write down the weight in the lab notebook.
12.) Over again do the experiment using 10, 15, 20, 25, 30, and 35 ml of vinegar.
Questions
1) The ratio between the mass of the Alka-Seltzer and the mass of the tablet are the same because it is a homogenous mixture. The homogenous mixture of Alka-Seltzer tablet components are equally mixed in the entire tablet.Therefore, the percent of the Alka-Seltzeris same in half mass of the tablet or even 1/4th mass of tablet. So, it remains constant. Law of constant composition.
2) The graph show that the relationship between the mass percentage and the acetic acid is directly proportion, so as the volume of vinegar increases the mass percentage increases so we can determine the amount of NaHCO3 in Alka-Seltzer by knowing the amount of vinegar needed.
Post Lab Questions
1. Is the gas produced in this experiment really an "ideal" gas? Explain.
2. The production of gas in this experiment is fairly slow, but its production in a car airbag is quite rapid. What is the reason for the difference in the two reactions?
Attachment:- Lab_Assignment.rar