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OWLv2 lOnline teaching and learning resource from Cengage Learning-Google Chrome

ID: 483157 • Letter: O

Question

OWLv2 lOnline teaching and learning resource from Cengage Learning-Google Chrome O east cen take CovalentActivity do?locato assignment take&takeAssignmentsessionLocator; assignment take Chapter 12: EOC The aluminum in a 1.328-g sample of impure ammonium aluminum sulfate was precipitated with aqueous ammonia as the hydrous Al2Os H2O. The precipitate was filtered and Question 1 1 pt ignited at 1000°C to give anhydrous Al203, which weighed 0.1880 g. Express the result of this analysis in tems of Question 2 1pt a. NH Al (SO Question 3 1 pt b. Al20 Question 4 1 Pt Question 5 1 pt Question 6 1pt Submit Answer Try Another Version 3 item attempts remaining Question 7 1 pt Progress 07 items Due Feb 14 at Previous 05:00 PM Finish Assig nment nstructor Save and Exit Cengage Learning l Cengage Technical Support 5:35 PM a Search X

Explanation / Answer

MW = molecular weight

(a)   % NH4Al(SO4)2
  
Mass of NH4Al(SO4)2 = mass Al2O3 x (2 * MW of NH4Al(SO4)2 / MW of Al2O3)
= 0.188 g x (2*237.15/101.96)
                                              = 0.8745 g g
% NH4Al(SO4)2 = (mass NH4Al(SO4)2 / total mass of the sample ) x 100
                                             = (0.8745 g/1.328 g) x 100

                                            = 65.8 %

Therefore,

% NH4Al(SO4)2 = 65.8 %


(b)   % Al2O3


% Al2O3 = (mass of Al2O3 / total mass of the sample ) x 100

                               = (0.188 g/1.328 g) x 100%

                               = 14.15 %

Therefore,

% Al2O3 = 14.15 %


(c)   % Al


Mass of Al = mass Al2O3 x (2 x Al / MW of Al2O3)
                   = 0.188 g x (2x 26.98 g/101.96 g)
                 = 0.1 g

Then,
% Al = ( mass of Al/ total mass of the sample) x 100

                        = ( 0.1 g / 1.328 g ) x 100

                        = 7.53 %

Therefore,

% Al = 7.53 %