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46 Chapter 3 Molecules, Compounds, and Chemical Equations (d) Given: 1.87 mol C₈H₁₈ Find: mol H atoms Conceptual Plan: Mol C₈H₁₈ mole H atom 18 mol H 1 mol C₈H₁₈ 18 mol H Solution: 1.87 X = 33.7 mol H atoms 1 Check: The units of the answer (mol H atoms) are correct. The magnitude is reasonable because it is greater than the original mol C₈H₁₈. 3.83 (a) Given: 8.5 g NaCl Find: g Na Conceptual Plan: g NaCl mole NaCl mol Na g Na 1 mol NaCl 1 mol Na 22.99 g Na 58.44 g NaCl 1 mol NaCl 1 mol Na Solution: 8.5 g NaCI X 58.44 1 g NaCI X 1 1 mol mol Na X 22.99 1 Na = 3.3 g Na Check: The units of the answer (g Na) are correct. The magnitude is reasonable because it is less than the original g NaCl. (b) Given: 8.5 g Na₃PO₄ Find: g Na Conceptual Plan: g mole mol Na g Na 1 mol Na₃PO₄ 3 mol Na 22.99 Na 163.94 g 1 mol 1 mol Na Solution: 8.5 g X 163.94 1 X 1 3 mol Na X 22.99 1 Na = 3.6 g Na Check: The units of the answer (g Na) are correct. The magnitude is reasonable because it is less than the original g Na₃PO₄. (c) Given: 8.5 g NaC₇H₅O₂ Find: g Na Conceptual Plan: g NaC₇H₅O₂ mole NaC₇H₅O₂ mol Na g Na 1 mol NaC₇H₅O₂ 1 mol Na 22.99 g Na 144.10 g NaC₇H₅O₂ 1 mol NaC₇H₅O₂ 1 mol Na Solution: 8.5 X 144.10 1 g X 1 1 mol Na X 22.99 1 mol Na Na = 1.4 g Na Check: The units of the answer (g Na) are correct. The magnitude is reasonable because it is less than the original g NaC₇H₅O₂. (d) Given: 8.5 g Find: g Na Conceptual Plan: g mole mol Na g Na 1 mol 2 mol Na 22.99 g Na 236.1 g 1 mol Na₂C₆H₆O₇ 1 mol Na Solution: 8.5 X 236.1 1 X 1 2 X 22.99 1 mol Na Na = 1.7 g Na Check: The units of the answer (g Na) are correct. The magnitude is reasonable because it is less than the original g 3.85 Given: 5.85 g C₂F₄ Find: F atoms Conceptual Plan: g mol molecules F atoms 1 mol 6.022 10²³ molecules 4 F atoms 100.02 g C₂F₄ 1 mole 1 C₂F₄ molecule 1 mol 6.022 X 10²³ molecules 4 F atoms Solution: 5.85 X X 100.02 1 1 = 1.4089 X 10²³ F atoms = 1.41 X 10²³ F atoms Check: The units (F atoms) are correct. The magnitude of the answer (1.41 X 10²³) makes physical sense because there is 0.06 mole of molecules and there are 4 F atoms in each molecule. Copyright © 2017 Pearson Education, Inc.