The Blue Bottle Reaction: An Exercise in Observation and Deductive Reasoning Skills
Essay by meaghan.murphy31 • January 18, 2016 • Lab Report • 2,591 Words (11 Pages) • 1,477 Views
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The Blue Bottle Reaction: An exercise in observation and deductive reasoning skills
By Meaghan Murphy
Lab Partner: Lindsey Izzo
Introduction
The blue bottle reaction is a primary experiment that demonstrates the ability to make simple observations on a more complicated reaction. An ingredient used in the reaction was methylene blue: a heterocyclic aromatic chemical compound typically used as a stain and a pharmaceutical drug which becomes blue when dissolved in water. Looking at the lab prior, it is possible that excluding one of the ingredients could play a major impact on the outcome of the reaction. Several of the beginning questions deal with the possibilities of leaving out one of the ingredients and observing what would happen to the reaction time.
Beginning Questions
The beginning questions for the blue bottle reaction were proposed by individual lab groups which lead to the investigation of what would occur in the bottle. Our group’s question was, “Does the amount of methylene blue make the ring darker?”
- How does altering the amount of ingredients affect the blue to clear color change time?
- Why does the methylene blue rise to the top?
- How does the amount of Vitamin C affect reaction time?
- Does the amount of salt affect the rate of the reaction?
- What affect occurs to methylene blue when NaCl is altered?
- Does the amount of water alter the reaction?
- How does an increase in temperature alter the time it takes for the solution to turn clear?
- What are the effects of the amount of Copper Sulfate on the reaction?
Procedure
The Standard Reaction
This standard procedure was carried out by each lab group in order to see the same results given through the set of instructions which allowed for a basic control.
- A bottle was filled with clean, clear, colorless –ml bottle approximately two-thirds full of water. The water level was marked on the outside of the bottle with a marker or a piece of tape. The bottle was filled to the line each time the reaction was repeated.
- Added to the bottle was 0.6 g of granular or powdered vitamin C, 3-4 drops of methylene blue solution (the solution was shook immediately after), and 0.5 g of table salt.
- The bottle was capped securely and shook to dissolve all the solids.
- The cap was removed and 4 drops of copper (II) sulfate solution were added.
- The bottle was recapped securely. It was shook for 20 seconds. Observations were recorded of the solution’s color, looking horizontally through the side of the bottle.
- The bottle was left undisturbed for a few minutes. Observations of the color were recorded.
Modifications to Step Two
Steps five and six will be repeated three additional times. For our beginning question, step two was altered in order to answer my beginning question. In step two, we kept the exact amounts of solids; however, we changed the amount of methylene blue. All the other steps stayed the same as the control. Two alternate trials were ran: two drops and eight drops. One step was changed with every group to find the answer to their specific questions. Changes like adding heat and altering step two by adding more NaCl were just some of the alterations made by the remainder of the groups.
Modifications to Other Groups
Question five modified step one by varying the amount of water in the jar. Instead of only testing two-thirds amount full, one-third and a full jar was tested as well. In question one through four, the groups all modified step two. For question one, the group changed the amount of each ingredient to observe the changes in the reaction. Another group examined why methylene blue rises to the top. It was done by withholding each ingredient to record the results of the reaction. Looking at question three, the amount of Vitamin C was changed and in question four, the amount of NaCl was changed to examine the reaction time. Question six and seven do not modify the procedure; however, the groups added an attentional step where heat was applied to the solution. Finally, question eight modified step four in varying the amount of copper (II) sulfate to observe the change in reaction time.
Results
Trial | Methylene Blue Drops | Time (min) | Observations |
Control | 4 | 3 | The solution went from a medium blue to clear in approximately 3 minutes. The blue ring was a medium blue as well. |
Trial 1 | 0 | 0 | Since there was no methylene blue, there is no way for the solution to turn blue. |
Trial 2 | 2 | ≈1.5 | The solution went from a light blue to clear in a short amount of time. There was still a blue ring; however, the blue ring was not noticeably visible. It was more concentrated towards the outside. |
Trial 3 | 8 | ≈5 | The solution went from a very dark blue to clear in a longer amount of time. The blue ring was very visible and was blue throughout the top. |
The observations from our group’s experiment are seen in Table 1.
Table 1. The effects of altering the amount of methylene blue on the blue bottle reaction.
Tables 2-3 are focused on how methylene blue is affected by alternating many different variables including changing the amount of the ingredients or examining its behavior. Table 4 is concerning the amount of Vitamin C added and how the reaction time will vary. Table 5-7 concentrates on the effects of NaCl on the reaction time and how methylene blue reacts while table 8 demonstrates the change on how fast the solution turns clear varying with different water levels. Tables 9-10 concentrate on how temperature affects the time in with the solution turns clear. Finally, table 11 generalizes the effect of adding more or less CuSO4.
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