1 / 32

Mole Problems

Mole Problems. Calculating molar mass. Round all masses to the 10ths place. Calculate the molecular weight of F e 2 O 3. Step One: two atoms of iron and three of oxygen Step Two: Fe = 55.8 amu and O = 16.0 amu Step Three: (2 x 55.8) + (3 x 16.0)

Download Presentation

Mole Problems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Mole Problems

  2. Calculating molar mass Round all masses to the 10ths place

  3. Calculate the molecular weight of Fe2O3 • Step One: two atoms of iron and three of oxygen • Step Two: Fe = 55.8 amu and O = 16.0 amu • Step Three: (2 x 55.8) + (3 x 16.0) • Step Four: 111.6 + 48.0 = 159.6 amu (grams) for one mole

  4. Calculate the molecular weight of KClO4 • Step One: one atom of potassium, one of chlorine, and four of oxygen. • Step Two: K = 39.1 amu, Cl = 35.5 amu, O = 16.0 amu • Step Three: (1 x 39.1) + (1 x 35.5) + (4 x 16.0) • Step Four: 39.1 + 35.5 + 64.0 = 138.6 amu (grams) for one mole

  5. Calculate the molecular weight of (NH4)2S • Step One: two atoms of nitrogen, eight of hydrogen and one of sulfur • Step Two: N = 14.0 amu, H = 1.0 amu, S = 32.1 amu • Step Three: (2 x 14.0) + (8 x 1.0) + (1 x 32.1) • Step Four: 28 + 8.0 + 32.1 = 68.1 amu (grams) for one mole

  6. Calculate the molar mass of Al(NO3)3 • Calculate the molar mass of Al(NO3)3 • Al(1 x 27.0) + N(3 x 14.0) + O(9 x 16.0) = • 213.0 amu (grams) is the mass of one mole of aluminum nitrate.

  7. You Try These… • 1. AlCl3 • 2. Ba(SCN)2 • 3. LiH • 4. Ba(BrO3)2 • 5. AlBr3 • 6. HCl

  8. Answers • 1. 133.5 g/mol • 2. 253.5 g/mol • 3. 7.9 g/mol • 4. 393.1 g/mol • 5. 266.7 g/mol • 6. 36.5 g/mol

  9. GRAMS to MOLES Round all final answers to 3 sig figs

  10. Convert 25.0 grams of KMnO4to moles. • KMnO4 =158.0 g / mole of KMnO4 • Now let’s solve it • 25.0 g x 1 mole = 0.158191804 moles 158.0 g • 0.158 moles

  11. Calculate how many moles are in 17.0 grams of H2O2. • H2O2 = 34.0 g / mole • Now, let’s solve it • 17.0 g x 1 mol H2O2= 0.5 moles 34.0 g • 0.500 moles

  12. You try these… • Calculate the moles present in: • 1) 2.00 grams of H2O • 2) 75.57 grams of KBr • 3) 100. grams of KClO4 • 4) 8.76 grams of NaOH • 5) 0.750 grams of Na2CO3 • Remember to round answers to 3 sig figs

  13. Answers • 1) 0.111 moles • 2) 0.635 moles • 3) 0.722 moles • 4) 0.219 moles • 5) 0.00708 moles

  14. MOLES TO GRAMS Round all answers to 3 sig figs

  15. Calculate how many grams are in 0.700 moles of H2O2 • H2O2 molar mass = 34.0 grams/mole • 0.700 moles x 34.0 grams = 23.8 g 1 mole • 23.8 grams

  16. Convert 2.50 moles of KClO3 to grams. • KClO3 molecular mass = 122.6 g/mole • 2.50 moles x 122.6 g = 306.5 grams 1 mole • 307 grams

  17. You try these… • Calculate the grams present in: • 1) 0.200 moles of H2S • 2) 0.100 moles of KI • 3) 1.500 moles of KClO • 4) 0.750 moles of NaOH • 5) 3.40 x 10-5 moles of Na2CO3 • Remember to round answer to 3 sig figs

  18. Answers • 1) 6.82 grams • 2) 16.6 grams • 3) 136 grams • 4) 30.0 grams • 5) 0.00360 grams

  19. Avogadro's Number 6.02 x 1023 particles = 1 mole Particles can mean atoms or molecules

  20. One mole of ANY specified entity contains 6.02 x 1023 of that entity

  21. For Example • One mole of donuts contains 6.02 x 1023 donuts • One mole of H2O contains 6.02 x 1023 molecules • One mole of nails contains 6.02 x 1023 nails • One mole of Fe contains 6.02 x 1023 atoms

  22. Continued • One mole of dogs contains 6.02 x 1023 dogs • One mole of electrons contains 6.02 x 1023 electrons • One mole of Chemistry students contains 6.02 x 1023 poor, suffering (I mean happy, joyful) high school students

  23. 0.450 mole of Fe contains how many atoms? • 0.450 mole Fe x 6.02 x 1023 atoms 1 mole • = 2.709x1023 atoms • Final, rounded answer: 2.71x1023 atoms

  24. 0.200 mole of H2O contains how many molecules? • 0.200 mole x 6.02 x 1023 atoms 1 mole • = 1.204x1023 atoms • Final, rounded answer: 1.20x1023 atoms

  25. You try these… • 1) Calculate the number of molecules in 1.058 mole of H2O • 2) Calculate the number of atoms in 0.750 mole of Fe • Remember to round to 3 sig figs

  26. Answers • 1) 6.37x1023 molecules • 2) 4.52x1023 atoms

  27. Two Step Problems Grams to particles OR particles to grams Grams to atoms OR atoms to grams If MOLE is not stated, it’s a two step problem ROUND ALL ANSWERS TO # SIG FIGS

  28. 0.450 gram of Fe contains how many atoms? • 0.450 g x 1 mole Fe x 6.02x1023 atoms = 55.8 g 1 mole • 4.8548387x1021 atoms • Final answer = 4.85x1021 atoms

  29. 0.200 gram of H2O contains how many molecules? • H2O molecular mass = 18.0 g • 0.200 g x 1 mole H2O x 6.02x1023 molecules 18.0 g 1 mole • 6.6838888889x1021 molecules • Final answer = 6.68x1021 molecules

  30. You try these… • 1) Calculate the number of molecules in 1.058 gram of H2O • 2) Calculate the number of atoms in 0.750 gram of Fe • Remember to round answer to 3 sig figs

  31. Answers • 1) 3.54x1022 molecules • 2) 8.10x1021 atoms

  32. THE END

More Related