1 A 532 78 g sample of AlxGayAsz was found to contain 339 11 g of Ga and 156 16 g of As a Find the empirical formula for AlxGayAsz CH 201Self Study Worksheet 1 532 78 g 339 11 g 156 16 g 37 51 g Al 37 51 g 26 98 g mol 1 39 mol Al 339 11 g 69 72 g mol 4 86 mol Ga 156 16 g 74 92 g mol 2 08 mol As Divide by the smallest Al1Ga3 5As1 5 Whole numbers Al2Ga7As3 is the empirical formula b If the molecular weight is 766 76 what is the molecular formula 2 x 26 98 g mol 7 x 69 72 g mol 3 x 74 92 g mol 766 85 g mol the molecular formula is Al2Ga7As3 2 For Mg ClO4 2 a Find the mass of Mg Cl and O MW of Mg ClO4 2 1 x 24 31 g 2 x 35 45 g 8 x 16 00 g 223 21 g Mg 24 31 g 223 21 g x 100 10 89 Mg Cl 2 x 35 45 g 223 21 g x 100 31 76 Cl O 8 x 16 00 g 223 21 g x 100 57 35 O b How many grams of Mg ClO4 2 would contain 7 38 g of chlorine 7 38 g Cl 0 3176 g Cl g Mg ClO4 2 23 2 g Mg ClO4 2 c How many moles of magnesium are contained in 230 57 g of Mg ClO4 2 230 57 g Mg ClO4 2 x 0 1089 g Mg g Mg ClO4 2 24 31 g Mg mol 1 033 mol Mg 3 Balance the following chemical reaction with the smallest whole number coefficients AlCl3 H2O O2 Al HClO3 a How many grams of water are required to react with 3 57 g of AlCl3 3 57 g AlCl3 26 98 g mol 3x35 45 g mol 0 02678 mol AlCl3 0 02678 mol AlCl3 x 6 mol H2O 4 mol AlCl3 x 18 g mol H2O 0 723 g H2O b How many grams of Al will be formed 0 02678 mol AlCl3 x 4 mol Al 4 mol AlCl3 x 26 98 g mol Al 0 723 g Al 4 For the following reaction CH 201Self Study Worksheet 1 Zr2O5 2 H2 Zr2O3 2 H2O a If you began with 216 g Zr2O5 and 107 g of H2 which is the limiting reagent 0 823 mol Zr2O3 1 mol Zr2O3 216 g Zr2O5 107 g H2 mol Zr2O5 262 44 g Zr2O5 mol H2 2 g H2 1 mol Zr2O5 2 mol H2 1 mol Zr2O3 26 8 mol Zr2O3 Zr2O5 is the limiting reagent b How many grams of the non limiting reagent are left after the reaction is complete 0 823 mol Zr2O3 x 2 mol H2 x 2 g H2 3 292 g H2 used up 1 mol Zr2O3 1 mol H2 107 g 3 292 g 104 g H2 excess c How many grams of Zr2O3 would be formed 0 823 mol Zr2O3 1 mol Zr2O3 x 230 44 g Zr2O3 190 g Zr2O3 would be made 5 a For the following reaction how many grams of carbon are needed to have a 20 0 excess with 3 765 g of water Hint excess amount leftover amount used up x100 C s H2O l C3H4O2 l 3 765 g H2O 3 765 g C 1 20 4 518 g C for a 20 excess 3 mol C 2 mol H2O mol H2O 18 g H2O mol C b What is the theoretical yield in grams for C3H4O2 l 12 g C 3 765 g C for stoich reaction 3 765 g H2O mol H2O 18 g H2O 1 mol C3H4O2 72 g C3H4O2 7 530 g C3H4O2 2 mol H2O mol C3H4O2 c What is the yield if the actual yield is 5 31 g 5 312 g 7 530 g 100 70 54 6 a Please fill in the following reaction table in moles for 45 21 g Cu2O3 12 77 g N2 and 24 05 g O2 Remember to balance the reaction first Initial Final Cu2O3 0 2582 0 1002 0 1580 45 21 g Cu2O3 175 1 g mol 0 2582 mol Cu2O3 12 77 g N2 28 02 g mol 0 4557 mol N2 24 05 g O2 32 00 g mol 0 7516 mol O2 N2 0 4557 0 3006 0 1551 0 7516 0 7516 0 000 O2 Cu NO3 3 0 000 0 2004 0 2004 b How many grams of Cu NO3 3 are formed 0 2004 mol Cu NO3 3 249 55 g Cu NO3 3 mol 50 01 g Cu NO3 3 c What is the excess of the two non limiting reagents 0 1580 mol 0 1002 x 100 157 7 excess Cu2O3 0 1551 mol 0 3006 mol x 100 51 60 excess N2
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