The Atomic Mass Of Pure Aluminum

2516 Words Sep 29th, 2016 11 Pages
Introduction This experiment had two objectives: 1) to determine the atomic mass of pure aluminum, and 2) to determine the masses of aluminum and zinc in an unknown aluminum alloy. To fulfill both of these objectives, both pure aluminum and the unknown alloy were reacted with HCl in order to produce a chemical and H2 gas. The reaction of aluminum and zinc with HCl are found below:
2Al(s) + 6HCl(aq) ⟶ 2AlCl3(aq) + 3H2(g)
2Zn(s) + 6HCl(aq) ⟶ 2ZnCl3(aq) + 3H2(g) Both metal samples would dissolve into liquid HCl, producing a H2 gas which would then displace grams of H₂O into a previously weighed beaker. The increased mass of the beaker was then used to determine the amount of moles of H2, which was subsequently used to determine the moles of aluminum reacted. Using the first reaction shown above and molar mass ratios, the atomic mass of the pure aluminum sample was found, fulfilling the first objective. A provided formula in the lab manual was then used to convert moles of H2 into a mass fraction of aluminum in the unknown alloy, completing the second objective. Results for both reactions were measured and calculated with the use of provided formulas found in the lab manual.

Observations and Procedure Four trials were conducted in this experiment. The first two trials were set up to ultimately record the experimental molar mass of aluminum, and the last two trials were set up to record the percentages of aluminum to zinc in an unknown alloy. The purpose of two trials for…
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