Galvanized Nail free essay sample

The purpose of this experiment was to find a sufficient price to charge for galvanizing nails. In order to do this the mass of zinc coating on a typical galvanized nail needs to be known. Two different methods were used to obtain these values. Gravimetric analysis was used by measuring the mass of the nail with the zinc coating and then subtracting the mass of the nail after the zinc was dissolved in acid. Gasometric analysis was used by measuring the total hydrogen yield of the reaction. Stoichiometry was then used to find a molar ratio between hydrogen and zinc. After calculating the moles of zinc, the mass can then be figured by multiplying by the molar mass of zinc. Experimental Procedure. First an apparatus needed to be set up to measure the hydrogen gas given off in the reaction of the zinc on the nail and the hydrochloric acid. A Erlenmeyer flask was used to hold the acid and nail which released the hydrogen into a rubber tubing that was fed into a 100 mL graduated cylinder full of water. We will write a custom essay sample on Galvanized Nail or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page As the hydrogen entered the upside down cylinder, it displaced the water, and the volume of gas was measured (gasometric analysis). The ideal gas law was then used, PV = nRT. Since the volume, temperature, gas constant (R), and pressure are known, the amount of moles of hydrogen can be figured and then converted to mass. The water vapor pressure also was subtracted from the measured pressure in the lab to obtain the correct pressure of hydrogen. The values obtained for the three nails using Gasometric analysis were 0. 0815, 0. 0846, and 0. 269 grams. After the stopping point of the zinc reaction, the nail was removed from the acid and weighed again. The initial mass of the nail minus the final mass of the nail equaled the mass of zinc: mi mf = mzinc (gravimetric analysis). The three gravimetric values obtained were 0. 114, 0. 088, 0. 117 grams. Results. NailsGravimetric AnalysisGasometric AnalysisPercent Difference 10. 114g0. 815g33. 25% 20. 088g0. 846g3. 94% 30. 117g0. 127g8. 12% A verage0. 1063g. 0977g8. 5% Overall Average of gravimetric and Gasometric = . 102 grams These values compared to the class had much less percent difference. Many of the other values varied widely, but the main group floated around . 08 to 1. 2 grams. The average percent difference was fairly low for this data and shows somewhat accurate measurements. Discussion. The data showed an overall average of about . 1 grams of zinc per nail. Compared to the average total mass of the three nails (2. 74 grams), we measured an average of 3. 7% zinc on each nail. When we calculated the price of production, and found that it would cost 4,080,000 dollars to galvanize 5 billion nails. The original problem stated that they were charging 500,000 dollars, which according to our calculations is an extreme underestimate. The company would be losing a lot of money. Our percent error was low for the most part, except for nail 1. This shows that the measurements must have been at least in the ball park of the correct amount of zinc. The classes percent differences varied greatly and most were higher than our. The high variance in class’s measurements shows the potential for a lot of human error. The same human error could be the cause of our high percent difference with nail number 1. Since it was the first experiment we were doing, we could have made several mistakes, either reading measurements or not filling the graduated cylinder completely. Also the stopping point of the zinc reaction with hydrochloric acid was very subjective. There was no way to be sure that all of the zinc had dissolved, or if iron had began to dissolve. This could cause skewed measurements of the mass of zinc. In conclusion our lab was successful in finding out the production cost of galvanizing 5 billion nails. There may however be some variance due to human error.