I'm Blowing Bubbles Forever



Blowing Bubbles

Douglas Brunson & Coy Ralley

Professor Christine Boese

English 102 – 101

English Department at Clemson University

March 11, 1999

Dbrunso@clemson.edu

Rralley@clemson.edu

Abstract:

As baking soda and vinegar were reacted the volume of gas created by the reaction was recorded. This data was then analyzed for the purpose of estimating the volume release when a known volume of vinegar and baking soda is being reacted. This project was undertaken for the experience in solving a problem in a team atmosphere. The gas was collected in an apparatus designed by the members of the team that had a rudimentary understanding of chemistry. As more baking soda and vinegar were reacted there was a larger volume of gas released.

Introduction: Statement of the Problem

The reaction of baking soda and vinegar is very common. It is the same reaction that many middle school students use for volcano science projects. The reaction is relatively safe because carbon dioxide, water, and salt are the only products. The purpose of this project was to develop an apparatus that would allow us to measure the amount of gas released in this reaction. When the baking soda and vinegar were combined the volume of gas created by the reaction was recorded in an apparatus designed by the members of the team that had a rudimentary understanding of chemistry. The data was analyzed, and the information gained provided an adequate estimation of the volume of gas released when a known quantity of vinegar and baking soda was combined. We then dimensionally plotted the results from our tests. Dimensional analysis of the situation was done to produce dimensionless parameters for the reaction. The results were plotted in such a way that all of our tests fell on a single plot curve. The group researched the chemical formulas of the two reactants to determine a chemical formula for the reaction.

This project helped teach the group how to think creatively and work together as a team. The project taught how to use ones resources to the fullest. Since the outcome of the results could be determined mathematically using chemistry, performing this experiment allowed the researchers to test a self-designed experiment and the methods of gathering and analyzing of data that it produced. Even though the outcome of the experiment was predictable, the experiment must be performed in order to assure that the expected calculations were correct.

Methods and Materials:

The method of the project could have been based on trial and error, but the group members brainstormed and chose a method of doing the project. The method chosen and the process for testing the amount of a gas produced via the reaction were based on the knowledge of chemistry. The chemical reaction took place in a beaker. A stopper was used to form an air tight seal between the reaction environment and the open air. The tube was the only escape path from the beaker to the measuring area (the graduated cylinder). The tube was submersed in the dish of water with the open end point up into the graduated cylinder, which was also filled with water. The open end of the cylinder was submerged in the dish of water. The tube allowed the gas to escape out of the reaction container and flow to the cylinder, thereby replacing the water with gas. The volume of gas created by the reaction was equal to the amount of water displaced. The apparatus and the gas were constantly held and recorded at 1atm of pressure. Unlike other inferior designs, this design eliminates the problem of dealing with pressure as a variable factor. The gas was chemically created through the reaction in the glass bottle and traveled through the tube.

The materials used were:

• One 250 mL beaker

• One fitted stopper with an airtight opening for a tube

• One 2 inch high pan filled with water

• One graduated cylinder

• One rubber tube (1/2 cm diameter aperture and 2mm wall thickness)

The construction of the experiment was as follows:

1. An excess amount of baking soda (approximately two tablespoons) was placed in the beaker first. See figure below.

2. The graduated cylinder was put in the pan, filled with water, and inverted so that it was standing upright with the bottom pointing upwards, and still filled with water. See figure 2.

3. Then the tube was attached to the stopper, and ran from the stopper, under the water in the pan, to inside the graduated. The collection area consisted of the graduated cylinder full of water inverted in the pan of water resembling a barometer. Since the collection area was similar to a barometer, it will, like a barometer, measure any volume in the graduated cylinder at the local atmospheric pressure (assumed to be 1 atm). The tube carried the gas to the graduated cylinder for measurement. See figure 3.

4. The desired amount of measured vinegar is poured into the beaker, and the stopper is quickly fitted over the top. The reaction takes place. See figure 4.

As the vinegar reacts with the baking soda, the gas inside the graduated cylinder was bubbled out. Therefore, it was simple to record the amount of gas in the graduated cylinder by looking at the volume of water displaced by air. Since the vinegar was the limiting reactant, since the reaction constant (K) at room temperature was so large, and since the reaction happened so quickly, then it was assumed that the reaction went to completion before measurements were taken.

The entire apparatus is shown in figure 5.

Thin glass cylinder Stopper

Tube Baking soda & vinegar

react in this.

Dish filled with water.

The group developed the design and revised it as errors and problems occurred. The series of experiments were then performed. We determined how and what range of experiments could be run considering the problems with and the limitations of our device. The group decided to leave the amount of baking soda constant. However as long as the amount exceeded that which would designate it as one spoon full of baking soda was placed in the large glass container each time the experiment was run. The group varied the amount of vinegar placed into the large glass container. The group placed a range of vinegar from one unit to two units. The units were the same as the units used to measure the amount of gas collected. One member of the group was the recorder while the rest of the group was actively conducting the experiment. Another member of the group was responsible for measuring out the quantities of baking soda and vinegar each experiment. The two other member of the group actually ran the experiment. As one member poured the vinegar into the large glass container that contained the baking soda, another member placed the stopper, with connected rubber tubing, over the hole of the large glass container. The gas from the reaction then flowed through the tube. When the gas reached the thin glass cylinder, it rose to the top as bubbles and displaced the water into the dish. After the water level in the thin glass cylinder became constant, a member of the group determined the amount of gas that was created based on the lines on the cylinder. The group repeated the experiment several times with varying amounts of vinegar. The group did the experiment with three different amounts of vinegar, and then tested each amount three times each to get a better picture of the reaction by seeing the average.

Results:

The group came up with the following results.

|Amount of |Gas Produced |Gas Produced |Gas Produced |

|Vinegar |Trial #1 |Trial #2 |Trial #3 |

|1.0 mL |5.5 mL |9.0 mL |7.0 mL |

|1.5 mL |18.5 mL |10.5 mL |10.5 mL |

|2.0 mL |19.5 mL |31.0 mL |19.5 mL |

Discussion:

The results are highly varied. The variety of results can be explained by many factors. The factors include the escape of gas, the measurement of baking soda, and the reading of the units when measuring the vinegar and the gas. The escape of gas can happen in many different ways: the stopper could not have been placed on the large glass container tightly, and/or the gas could have escaped through the tube connection. Taking the average of the results would give a more accurate answer. This was the reasoning behind the three tests taken three times. When one milliliter of vinegar were reacted, there was 7.1 milliliters of gas created. When 1.5 milliliters of vinegar were reacted, 13.2 milliliters of gas were created. When 2 milliliters of vinegar were reacted, 23.3 milliliters of gas were created.

The majority of the time spent on this project was directed towards the development of the apparatus and the actual execution of the experiment. The experimental process combined with group interaction equipped the individuals of the team with beneficial knowledge such as how to share ideas and implement them as a team, and how to manipulate available materials to engineer a working apparatus. Once these principles have been instilled into the thought processes of the group’s individuals, they can be utilized in the future group work of many professional careers especially in any engineering field.

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Baking Soda

Figure 1:

H2O

H2O

Figure 2:

Figure 3:

Figure 4:

Figure 5:

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