Please help number 2 and 3A. thanks a lot :) Past-lab Questio 1. Determine how e

Question

Please help number 2 and 3A. thanks a lot :)

Past-lab Questio 1. Determine how each or the folowing actions wmid "ect the calcuated % magnesium in the magresum oxide compound. Would the pertentags be tao hign too Now, ar remain the same? A. The evaporation of water caused "spattering" B. Water was not completely removed by evaporation. 2. The white pawder often found on objects made of aluminum is aluminum oxide Al Oj. Cakulste the malar mass of the alumirum oxicu. A S.00 g strip of afuminum is reacted in air, producing an oxide weighing 9.36 g. Calculate the percent oxygen and aluminum in the compound. 3. Aluminum oxide has the empirical formular of Al0. A. Calculate the % aluminum in A10), using the chemical formula. B. Calculate the % error for the percent aluminum calculated in question 2, Re to itern 16 in the report sheet for calculation set-up.

Explanation / Answer

2 ) 4 Al + 3O2 --------------------> 2 Al2O3

     108 g     96g                             204 g

5 g      ?                                  9.36g

we need to find out first O2 mass

for 96g O2-----------------------> 204 g Al2O3

     ??? -----------------------------> 9.36 g Al2O3

O2 weight = 96 x 9.36 / 204

                  = 4.4 g

Al percentage = (Al mass / total Al2O3 mass ) x 100

                        = (5 / 9.36 ) x 100

                         = 53%

O2 percentage = (O2 mass / total Al2O3 mass ) x 100

                        = (4.4 / 9.36 ) x 100

                         = 47%

3) Al2O3 weigth = 102 g / mol

Al %   = (Al weight / total weight ) x 100

          = (2 x 27 / 102 ) x 100

           = 53 %

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