test answers - PLEASE DO NOT WRITE ON THIS TEST PAPER Arabia Mountain High School Chemistry Version A1 Make sure you write the test version on the

test answers - PLEASE DO NOT WRITE ON THIS TEST PAPER...

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PLEASE DO NOT WRITE ON THIS TEST PAPER Arabia Mountain High School Mole Concept and Stoichiometry Chemistry Use a #2 pencil to bubble the correct answer on the scantron. Version A1 Make sure you write the test version on the scantron ANSWER KEY ANSWER KEY 1. How many moles is 400.0 g of Al 2 (SO 4 ) 3 ? Mol = mass/molar mass Mol = 400.0g/342g/mol = 1.169 mol 2. Which is the percent composition of bromine in the compound NaBr? % Br = (mass Br/mass NaBr) x 100 % Br = (79.90g/102.88g) x 100 = 77.7% 3. How many molecules are in 3.6 grams of NaCl? Molecules NaCl = 3.6g NaCl x 6.02 x 10 23 NaCl molecules = 3.7 x 10 22 molecules 58.43g NaCl 4. How many grams are in 1.946 moles of NaCl? From Mol = mass/molar mass, Mass = mol x molar mass Mass NaCl = 1.946 mol x 58.43 g = 113.7 g 5. For the reaction: P 4 (s) + 5O 2 (g) P 4 O 10 (s), if 3 mol of phosphorus react with 10 mol of oxygen, the theoretical yield of phosphorus (V) oxide will be ________. From P 4 , Mol P 4 O 10 = 3 mol P 4 x 1 mol P 4 O 10 = 3 mol P 4 O 10 1 mol P 4 From O 2, Mol P 4 O 10 = 10 mol O 2 x 1 mol P 4 O 10 = 2 mol P 4 O 10 5 mol O 2 Therefore, O 2 is limiting reactant and the theoretical yield = 2 mol P 4 O 10 6. How many moles of sulfur will combine with 0.4 moles of carbon to form CS 2 ? C + 2S CS 2 1 mol 2 mol Mol S = 0.4 mol C x 2 mol S = 0.8 mol S 1 mol C 7. According to this chemical reaction, which is the number of grams of Fe produced from 14 moles of H 2 ? Fe 3 O 4 (s) + 4H 2 (g) 3Fe (s) + 4H 2 O (l) 4 mol 3(55.845)g gram Fe = 14 mol H 2 x 167.535 g Fe = 586g = 5.9 x 10 2 g Fe 4 mol H 2
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PLEASE DO NOT WRITE ON THIS TEST PAPER 8. Which is the correct mole ratio of K 3
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  • Spring '16
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