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Table 1 above shows the raw data of experiment I did to test the strength different electrolytic solutions. Moreover, this data table shows that all solutions except tap water and distilled water have the concentration of 0.5 M. In this table, some solutions’ ammeter reading has different uncertainty and multimeter setting. This is because solution like hydrochloric acid has high amp, so I had to set multimeter setting at 300mA in order to measure the ammeter reading of hydrochloric acid accurately.
On the other hand, solution like distilled water has extremely low amp, so I had to set multimeter setting at 0.3mA in order to measure the ammeter reading of distilled water accurately. Hence, varying in uncertainty of reading in each solution because as 1 reading, for example, if measured at setting of 300mA, is 5 amp per reading but if measured at 0.3mA, it is read as 0.005 amp per reading.
2.1. Data Processing
Table 2 is a processed data of experiment on investigation of the strength of different electrolytic solutions. I included average of the data about strength of each electrolytic solution to make the data table clearer. Furthermore, I also included standard deviation of the data, to summarize the spread of values around the mean. Lastly, I added additional information about these solutions, whether if they are acidic, basic or neutral solutions.
3.1 Conclusion and Evaluation
To conclude, the background information that was given to me by the instructor states that stronger acidic or basic solutions are stronger electrolytes than those of weaker acidic, basic or neutral solutions. Referring to Table 2, which is a processed data of acquired data from this experiment, it provides the information of solutions whether if they are acidic, basic or neutral. In addition, it shows that stronger acid and base tend to have higher ammeter reading and weaker acid and base or neutral solutions tend to have lower ammeter reading. For example, hydrochloric acid, which is a strong acid, transferred mean reading of 47amp, whereas acetic acid, which is a weak acid, transferred mean reading of 0.92amp. Therefore, the results I got through experiment yield to the background information given by the instructor. (NakanishMasaki)
Everytime I finished experimenting with one solution three times, I thoroughly washed plastic container and 2 carbon electrodes with tap water, which made direct contact with the solution while testing, and dried them with paper towel. The purpose is to avoid errors in results by preventing mix of preexisting solutions with another kind of solution. Moreover, since the fluctuation of the value that multimeter presented made hard for me to decide what to write as the data, whenever I fully connect complete electrical circuit, I waited for 15 seconds for the fluctuations to ease down. Finally, when I was performing experiment on calcium hydroxide (Picture 1), I mixed it by stirring with the glass pipe in order to uniformly spread the substance that was deposited on the bottom of the solution, so I can get uniformly mixed calcium hydroxide.
I did my best to cover up the weaknesses of lab equipment, but there still are some weaknesses still which were present throughout the lab, and it might have varied the data I collected. First of all, in order to follow the written instruction from the instruction sheets given, I had to wash equipments that made direct contact with the solution everytime I’m changing the solution that I will perform experiment upon with distilled water, but due to the lack of distilled water, I washed them with tap water instead.
Second of all, I am not sure if 15 seconds were enough time for the fluctuations of the value to settle, or maybe it was too much time. Last of all, whenever I finish mixing the calcium hydroxide, I have to transfer the solution to the smaller beaker for measurement, but it takes time to do that and the substance might have been settled down within the calcium hydroxide solution. Therefore, there were some errors that prevented me from collecting the best results.
Improvements can be made by providing each candidate, like me, with better lab equipments such as more advanced multimeter. Also, enough distilled water so I can wash equipments with it to follow the original instructions given.