Chem the Mole Homework

The Mole Homework Honors Chemistry Moles Problem Set 1. Determine the molar mass of each of the following compounds: a. HClO 1.01 + 35.45 + 16 = 52.46 g/mol b. (NH₄)₂S 2(14.01) + 8(1.01) + 32.07 = 68.17 g/mol c. Ca(NO₃)₂ 40.08 + 2(14.01) + 6(16) = 164.1 g/mol d. UF₆ 238.05 + 6(19) = 351.97 g/mol 2. Calculate the number of grams in 0.3 mol of each of the compounds listed in question one. a. 0.3 mol * 52.46 g/mol = 15.74 g b. 0.3 mol * 68.17 g/mol = 20.45 g c. 0.3 mol * 164.1 g/mol = 49.23 g d. 0.3 mol * 351.97 g/mol = 105.59 g 3. Calculate the number of moles contained in 100.0 g of each compound listed in question one. a. 100 g / 52.46 g/mol = 1.91 mol b. 100 g / 68.17 g/mol = 1.47 mol c. 100 g / 164.1 g/mol = 0.61 mol d. 100 g / 351.97 g/mol = 0.28 mol 4. In 3.01 x 10²⁴ molecules of water: a. How many moles of water are present? 3.01 x 10²⁴ molecules / 6.02 x 10²³ molecules/mol = 5 mol H₂O b. How many grams of water are present? 5 mol H₂O * 18.02 g H₂O/mol = 90.1 g H₂O 5. How many atoms are in 2.4 mol of Copper? 2.4 mol Cu * 6.02 x 10²³ atoms/mol = 1.44 x 10²⁴ atoms Cu 6. Calculate the molar mass of: a. NaHCO₃ 22.99 + 1.01 + 12.01 + 3(16) = 84.01 g/mol b. Mg(NO₃)₂ 24.31 + 2(14.01) + 6(16) = 148.33 g/mol c. (NH₄)₃PO₄ 3(14.01) + 12(1.01) + 30.97 + 4(16) = 149.12 g/mol 7. Calculate the mass of: a. 0.948 mol NaHCO₃ 0.948 mol * 84.01 g/mol = 79.64 g NaHCO₃ b. 3.67 mol Mg(NO₃)₂ 3.67 mol * 148.33 g/mol = 544.37 g Mg(NO₃)₂ c. 2.94 mol (NH₄)₃PO₄ 2.94 mol * 149.12 g/mol = 438.41 g (NH₄)₃PO₄ 8. Calculate the number of moles in: a. 9.67 g of NaHCO₃ 9.67 g / 84.01 g/mol = 0.115 mol NaHCO₃ b. 33.4 g of Mg(NO₃)₂ 33.4 g / 148.33 g/mol = 0.225 mol Mg(NO₃)₂ c. 0.754 g of (NH₄)₃PO₄ 0.754 g / 149.12 g/mol = 0.005 mol (NH₄)₃PO₄ 9. Calculate the percent composition of: a. NaHCO₃ Na: (22.99/84.01) x 100 = 27.37% Na H: (1.01/84.01) x 100 = 1.20% H C: (12.01/84.01) x 100 = 14.30% C O: 3(16/84.01) x 100 = 57.14% O b. Mg(NO₃)₂ Mg: 24.31/148.33 = 16.34% Mg N: 2(14.01)/148.33 = 18.89% N O: 6(16)/148.33 = 64.72% O c. (NH₄)₃PO₄ N: 3(14.01)/149.12 = 28.19% N H: 12(1.01)/149.12 = 8.15% H P: 30.97/149.12 = 20.77% P O: 4(16)/149.12 = 42.92% O 10. Calculate the number of grams of oxygen in 25.0 g of: a. NaHCO₃ 25 g * (57.14%) = 14.29 g O b. Mg(NO₃)₂ 25 g * (64.72%) = 16.18 g O c. (NH₄)₃PO₄ 25 g * (42.92%) = 10.73 g O MOLES PROBLEM SET II 1. Determine the molar mass of the following compounds a. Fe₃(PO₄)₂ 3(55.85) + 2(30.97) + 8(16) = 357.49 g/mol b. Hemoglobin (C₂₉₅₂H₄₆₆₄FeO₈₃₂) 2952(12.01) + 4664(1.01) + 832(16) + 1(55.85) = 64458.52 g/mol 2. Tin (II) fluoride is added to toothpaste to prevent tooth decay. In 24 g of SnF₂, how many moles are present? 24 g SnF₂ * (1 mol SnF₂) / 156.69 g SnF₂ = 0.153 mol SnF₂ 3. How many moles of benzene (C₆H₆) are present in 15.6 g benzene? 15.6 g C₆H₆ * (1 mol C₆H₆) / 78.12 g C₆H₆ = 0.200 mol C₆H₆ 4. How many grams of NH₄Cl are present in 0.4 mol of ammonium chloride? 0.4 mol NH₄Cl * 53.5 g NH₄Cl / 1 mol NH₄Cl = 21.40 g NH₄Cl 5. Define molar mass Mass of one mole of a pure substance 6. Calculate the molar mass of a compound if 0.22 mol of it weighs 48 g. 1 mol / 0.22 mol = 48 g / x g x = 218.18 g/mol 7. Which sample contains the largest number of hydrogen atoms? a. 72 g H₂O b. 0.4 mol H₂O c. 0.8 g H₂ d. 6.02 x 10²³ molecules H₂ 8. Which of the following has more atoms: 2.4 g of He or 10.4 g of Cr? Show your work. 2.4 g He * (1 mol He / 4.00 g He) * (6.02 x 10²³ atoms He / 1 mol He) = 3.61 x 10²³ atoms He 10.4 g Cr * (1 mol Cr / 52.00 g Cr) * (6.02 x 10²³ atoms Cr / 1 mol Cr) = 1.20 x 10²³ atoms Cr He has more atoms.