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Let’s go over the 1.5.2 Homework questions !

Let’s go over the 1.5.2 Homework questions !. 1. Give the molar mass of the substances listed. Include units!!. Nitrogen Oxygen gas, O 2 Iron (III) chloride, FeCl 3 Aspirin, C 9 H 8 O 4. 14.01 g/mol. 2(16.0 g/mol) = 32 g/mol. 55.85 + 3(35.45) = 162.2 g/mol.

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Let’s go over the 1.5.2 Homework questions !

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  1. Let’s go over the 1.5.2 Homework questions!

  2. 1. Give the molar mass of the substances listed. Include units!! • Nitrogen • Oxygen gas, O2 • Iron (III) chloride, FeCl3 • Aspirin, C9H8O4 14.01 g/mol 2(16.0 g/mol) = 32 g/mol 55.85 + 3(35.45) = 162.2 g/mol 9(12.01) + 8(1.01) + 4(16.0) = 180.21 g/mol

  3. 2. What is the mass of 5 moles of calcium chloride, CaCl2? Molar mass of CaCl2: 40.08 + 2(35.45) = 110.98 g/mol 5 moles x 110.98 = 554.9 g g mol

  4. 3. If you have 40 grams of aluminum foil, Al, how many moles of aluminum atoms do you have? Molar mass of aluminum: 26.98 g/mol 40 g x 1 mol= 1.48 mol 26.98 g

  5. 4. If you have 0.20 moles of gold, how much would it weigh? Molar mass: 196.97 g/mole 0.20 moles x 196.97 = 39.4 g g mol

  6. 5. If you have 300 grams of glucose, C6H12O6, how many moles of glucose molecules do you have? Molar mass: 6(12.01) + 12(1.01) + 6(16.0) = 180.24 g/mol 300 g x 1 mol = 1.66 moles 180.24 g

  7. 6. Calculate the molar masses for the molecules methanol, CH4O, and ethanol, C2H6O. Molar mass of methanol: 12.01 + 4(1.01) + 16 = 32.06 g/mol Molar mass of ethanol: 2(12.01) + 6(1.01) + 16 = 46.09 g/mol • If you had 1 gram of methanol and 1 gram of ethanol, which would have more molecules? Methanol – the molecules weigh less so you need more of them to get the same mass

  8. 7. How many moles of H atoms are there in 2.0 moles of C2H6O molecules? Explain. In 1 mole of C2H6O molecule there would be 6 moles of hydrogen atoms. So if you have 2 moles of C2H6O then you have: 2 molC2H6O x 6 mol H = 12 mol H 1 molC2H6O

  9. 8. Which of these has the most moles of lead atoms? Show your work and explain your answer. • 1.0 grams of PbCl2 Molar mass: 207.2 + 2(35.45) = 278.1 g/mol b. 1.0 grams of PbCl4 Molar mass: 207.2 + 4(35.45) = 349 g/mol c. 1.0 grams of PbCO3 Molar mass: 207.2 + 12.01 + 3(16) = 267.2 g/mol 1 g = 0.0036 mol 278.1 1 g = 0.0029 mol 349 1 g = 0.0037 mol 267.2 IT TAKES MORE MOLES OF A LIGHTER SUBSTANCE TO EQUAL THE SAME MASS SO THE LIGHTEST MOLECULE WILL HAVE THE MOST MOLES g mol g mol g mol

  10. 9. Which has more moles of oxygen atoms, 153 g of BaO or 169 g of BaO2? Show your work! Molar mass BaO: 137.33 + 16 = 153.33 g/mol Molar mass BaO2: 137.33 + 2(16) = 169.33 g/mol 1 mole Oxygen atoms 153 g = 1 mol BaO 153.33 169 g = 1 mol BaO2 169.33 2 moles Oxygen atoms g mol g mol

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