Noteboom Asa Preeti Bhattacharjee Lab Report

Asa Noteboom, Dylan Minnich Preeti Bhattacharjee - 21059 2/12/2023 Galvanizing Nails, Quality Control, and an Introduction to Green Chemistry Purpose: This lab was conducted with the purpose of measuring the galvanization, (the process of coating iron with zinc) of a group of ten iron nails. The nails have each been coated with a layer of zinc to prevent the nail from rusting. When the nail comes into contact with a strong acid such as HCl, the layer of zinc will dissolve leaving the iron nail exposed without its coating. By measuring the masses (grams) of the galvanized nails before and after the reaction we were able to measure the mass of zinc coating on each of the nails, and determine whether or not it is up to the industry standard. Materials and Methods: As a part of our lab procedure, we first gathered five galvanized nails and measured them by their length and diameter using a ruler and calipers for the diameter. Next we determined the mass (in grams) of the nails by weighing them on the scale. We also made sure to use the same balance for every nail we weighed. Then we obtained a rack holding five test tubes each where we carefully measured out an even amount of hydrochloric acid (enough to cover the nail) into each of the five tubes. the next step involved requires a timer as we started a time for two minutes as soon as we dropped one of the nails into the solution. After the two minutes was done, we immediately removed the nails from the HCl by dumping it into our waste container then using forceps to retrieve the nail. After cleaning the nail off with distilled water and a cleaning sheet to ensure for more accurate results, we once again took the mass of the nail. Finally, we repeated these steps for the remaining nails until we had gathered the masses of all ten nails before and after their two-minute reactions with the hydrochloric acid. Data, Observations, Equations, and Calculations: Observations: - Raw HCl was yellow in color and transparent - None of the nails were the same measurements in length nor diameter - Nails were all similar in color as well as shape and texture since they were all lightish grey and slightly rough - When reacting with the nail, the HCl turns a cloudy gray color and no longer becomes transparent. - Upon reaction, bubbles form in the HCl as well as gas evaporating from the liquid HCl. - When neutralizing the waste the waste started out a more yellow transparent color and as we added the NaOH it turned a darker blueish green and when we added NaOH it would make an initial cloud like substance that would then dissipate after some mixing

Table 1: Collected Values of Galvanized Nail Pre and Post HCl Acid Bath Trial Length (mm) Diameter (mm) Radius (mm) Surface Area (mm^2) Initial mass (g) Total time (Mins) Final mass (g) 1 39.1 2.64 1.32 335 .9015 2.00 .7543 2 39.3 2.96 1.48 379 .8645 2.00 .7690 3 39.1 2.79 1.40 354 .9015 2.00 .7691 4 39.4 2.68 1.34 343 .9137 2.00 .7663 5 37.8 2.83 1.42 348 .8611 2.00 .7587 6 39.1 2.67 1.34 339 .8915 2.00 .7594 7 43.6 2.77 1.39 391 .9004 2.00 .8063 8 40.6 2.51 1.26 330 .8715 2.00 .7575 9 39.4 2.69 1.35 344 .8942 2.00 .7759 10 39.6 2.83 1.42 365 .9189 2.00 .7555 Table 2: Calculated Values of Table 1 in Regards to Zinc Removed From Galvanized Nail Sample Zn Mass Loss per nail (g) Percentage Mass loss (%) Mass Loss (g/mm^2) Mass Loss (oz/ft^2) Average Mass Loss (g/mm^2) 1 .147 -16.3 .000439 1.48 .000355 2 .0955 -11.0 .000252 .830 3 .132 -14.7 .000373 1.23 Average Mass Loss (oz/ft^2) 4 .147 -16.1 .000430 1.41 1.17 5 .102 -11.9 .000294 .968 6 .132 -14.8 .000389 1.28

Zn loss = (Initial mass)-(final mass) Zn loss = (.9015 g) - (.7543 g) Zn loss = .147g % Mass loss: % = ((Final Mass - Initial Mass)/Initial mass) x100 % = ((.7543 g - .9015 g)/.9015 g) x 100 % = -16.3 Mass loss in g/mm^2: Mass loss/unit area = (mass loss of zinc per nail)/(Surface area) Mass loss/unit area =(.147g)/ (335 mm^2 Mass loss/unit area = .000439 g/mm^2 Conversion of g/mm^2 to oz/ft^2: Mass loss/unit (area oz/ft^2) = (Mass loss in g/mm^2)((0.035724/(1.07x10^-5)) Mass loss/unit (area oz/ft^2) = (.000439 g/mm^2)(0.035724 oz)/(1g) (1mm^2)/(1.07x10^-5 ft^2) Mass loss/unit (area oz/ft^2) = 1.48 oz/ft^2 Average mass loss in g/mm^2: Avg = (Trial 1 value + Trail 2 value + … + Trail 10 value)/10 Avg = (.000439 g/mm^2 + .000252 g/mm^2 + … + .000448 g/mm^2)/10 Avg = .000355 g/mm^2 Average mass loss in oz/ft^2: Avg = (Trial 1 value + Trail 2 value + … + Trail 10 value)/10 Avg = (1.48 oz/ft^2 + .830 oz/ft^2 + … + 1.48 oz/ft^2)/10 Avg = 1.17 oz/ft^2 Claims: How well do the nails compare to the industry standard? Are the nails used in the laboratory investigation of high quality? The nails compare very sufficiently to the industry standard. The nails used in the laboratory are of high quality. Evidence and analysis: The claims made were that the nails used were up to the industry standard and that they were of high quality. This can be shown as the industry standard for the Galvanisation of nails is on the higher quality end 1 oz/ft^2 and on the lower quality end .28 oz/ft^2 and according to our second data table which shows the average mass loss in oz/ft^2 of zinc was to be roughly 1.2 ± .2 which mean that at the

lowest our nail our nails had 1.0 oz/ft^2 of zinc on them which is the highest expectation of the industry. Our data also aligned with the class data seeing as the class data data was also 1.2 ± .3 oz/ft^2 which is the exact same numbers as ours and only has a slightly higher potential standard deviation so the class data backs up our data very nicely. Our data as can be seen table 1 has very little variation except for one potential outlier showing that our data is overall very consistent and reliable seeing as we were able to produce awfully similar results in all ten trials which can be seen especially in the final mass column where almost all of our data was exactly the same at roughly 0.75 g final. All of our numbers can seen to be above the minimum of the industry standard of 0.28 oz/ft^2 since our lowest possible outcome according to our average is 1.0 with the ± .2 oz/ft^2 so that shows how our nails were very comfortably up to the industry standard in terms of galvanization. This is a common occurrence in the data and also it can be seen that the only slight changes are most likely due to human error such as total mass after resting in the HCl test tube which can be most likely attributed to lack of exact timing further showing how even with these potential errors our data was still very consistent. Finally our nails were up to the industry standard and could be considered high quality nails since they on average had 1.2 ± .2 oz/ft^2 of zinc on each nail which is easily up to industry standard and would be considered high quality nails. Reflection: Some possible dilemmas that we could have run into during the experiment could have been involving the process when dunking the galvanized nails into the HCl solution. HCl is a highly corrosive acid and if we did not take the nails out at exactly two minutes, it could have led to some slight variation in our data. Also in one instance the timer did not start exactly when we dropped the nails in the solution, it was pressed a second or two after. This could also have led to some minor differences in our data. Both of these instances would be examples of some determinate errors that may have occurred during the experiment. One example of a minor indeterminate error that we came across was the subtle differences in dimensions between the nails, such as some small outliers in their length and diameter. For example one of our nails was 43.6 mm in length while most of the others were >40 mm in length. This was not a major issue however as we took the average of all ten of our nails, but certain nails could take slightly longer for the zinc to dissolve in the HCl if the nail is larger and has more zinc to dissolve than the others. Looking back at this experiment, one change we had to make was learning that we each had to conduct the experiment on five nails each rather than five as a pair. This caused a slight dilemma as we had already done the first nail together. If we were to revise this experiment we probably would have asked questions about this and been more clear in our procedure so we knew about this rather than facing any similar dilemmas. The process of galvanization is the process of coating iron with zinc. The purpose of this is to prevent the iron from rusting longer than it would without the coating. The zinc protects the iron from water abrasion which causes rusting. Even galvanized nails will still rust eventually, but they are of better quality than non-galvanized nails because they will have a longer time of use.