Mole intro and molar mass


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Mole intro and molar mass

  1. 1. CP Chemistry Semester 2 All rules outlined in the planner apply. NO FOOD NO DRINK NO PHONES If I see it you will be sent out.
  2. 2. Chemistry Semester Two: <ul><li>Math, Math, Math. You will need a calculator. A scientific calculator is listed in the course description as a requirement. Bring it. No sharing. If you don’t have a calculator on test or quiz day you will do the math without one. </li></ul><ul><li>Bring your book. You cannot use it if you don’t have it. No locker passes to get your book. </li></ul><ul><li>If you struggled semester one you will find semester two very difficult. I expect you to know everything from semester one and we will build on that knowledge. </li></ul>Not being prepared for class will result in a point deduction from every assignment when you do not have a book or calculator. NO EXCUSES.
  3. 3. The Mole <ul><li>The Mole is a unit of measurement for counting atoms or molecules. </li></ul><ul><li>Other counting units: </li></ul><ul><ul><li>one pair = 2 </li></ul></ul><ul><ul><li>one dozen = 12 </li></ul></ul><ul><ul><li>one gross = 144 </li></ul></ul><ul><ul><li>ONE MOLE = ? </li></ul></ul>
  4. 4. One mole = <ul><li>6.022 x 10 23 </li></ul><ul><li>602,200,000,000,000,000,000,000 </li></ul><ul><li>* Also known as Avogadro’s number. </li></ul>
  5. 5. Amadeo Avogadro (1776-1856) <ul><li>An Italian chemist and physicist, he is famous for his gas law, known as Avogadro’s law. It says that equal volumes of different gases at the same temperature and pressure contain the same number of atoms or molecules. </li></ul>
  6. 7. MOLES <ul><li>A mole of moles, placed head to tail, would stretch 11 million light years and weigh 9/10 as much as the moon! </li></ul><ul><ul><li>Assuming each mole is 17 cm long and weighs 100 g. </li></ul></ul>
  7. 8. <ul><li>Marbles, each 2.0 cm in diameter, would form a mountain 116 times the height of Mount Everest. The base of the mountain would be slightly larger than the United States! </li></ul>
  8. 9. COUNTING ATOMS <ul><li>Suppose that the Greek god Zeus, after observing the Big Bang 15 billion years ago, decided to count one mole of atoms. </li></ul><ul><ul><li>If he could count very fast (1 million per second) and never slept, today he would have completed over 3/4 of the task. </li></ul></ul><ul><ul><li>But he will not finish for another 4 billion years! </li></ul></ul>
  9. 10. <ul><li>One mole of marshmallows would cover the USA to a depth of of 1050 km (650 miles). </li></ul><ul><ul><li>Marshmallow volume is 16.4 cm 3 or 1.0 in 3 and the area of the USA is 9.32 x 10 6 km 2 </li></ul></ul>
  10. 11. MONEY IN PENNIES <ul><li>If you took 1 mole of pennies and evenly distributed them among the 4.9 billion human inhabitants of the earth: </li></ul><ul><ul><li>Each man, woman and child would have enough money to spend 1 million dollars every hour (day and night) and still have over half of it unspent at their death!!! </li></ul></ul>
  11. 12. PAPERCLIPS <ul><li>One mole of paperclips hooked end to end would wrap around the earth 400 trillion times!!! </li></ul><ul><ul><li>Each paperclip is approximately 2.5 cm in length. </li></ul></ul><ul><li>It would take you 190 million centuries to hook the paper clips together </li></ul><ul><ul><li>Assuming you put 1 million together per second </li></ul></ul>
  12. 13. M & M’s <ul><li>1 mole of M & M’s would stretch from here to the sun and back 200 billion times!!! </li></ul><ul><ul><li>Assuming an m&m is 1 cm in diameter and the distance to the sun is 93 million miles. </li></ul></ul>
  13. 14. GUACAMOLE <ul><li>Taco dip made from 1 mole of avocados </li></ul><ul><ul><li>Plus the approximate quantities of tomatoes, onion and chiles </li></ul></ul><ul><li>A train stretching to the North Star and back 2 1/2 times would be needed to transport the guacamole!!! </li></ul><ul><ul><li>Assuming the volume of one avocado is 278 cm 3 and that the other ingredients make up 25% of the total volume and average coal car has a capacity of 4000 ft 3 . </li></ul></ul><ul><ul><ul><li>The North Star is 680 light years away!!! </li></ul></ul></ul>
  14. 15. BUT… <ul><li>1 mole of water molecules would equal only ~1/3 of a cup. </li></ul>
  15. 16. The Mole is Helpful… <ul><li>in counting a large number of items if the items are EXTREMELY SMALL. </li></ul>
  16. 17. How to use the MOLE <ul><li>The mole is related to the periodic table. </li></ul><ul><li>Oxygen </li></ul><ul><ul><li>atomic mass = 16.00 AMU </li></ul></ul><ul><ul><li>molar mass = 16.00 grams </li></ul></ul><ul><li>Carbon </li></ul><ul><ul><li>atomic mass = 12.01 AMU </li></ul></ul><ul><ul><li>molar mass = 12.01 grams </li></ul></ul><ul><li>* The molar mass equals the mass of one mole of an element or compound. </li></ul>
  17. 18. ATOMIC MASS = MOLAR MASS <ul><li>Look @ periodic table: </li></ul><ul><li>1 mole of C = 12.01 g </li></ul><ul><li>1 mole of Na = 23.00 g </li></ul><ul><li>1 mole of N 2 = 28.02 g </li></ul><ul><ul><li>Nitrogen is diatomic , must add the two atoms together … </li></ul></ul><ul><li>1 mole of O 2 = 32.00 g </li></ul>
  18. 19. Molar Mass for Compounds <ul><li>Step 1: atom inventory </li></ul><ul><li>Step 2: multiply # of atoms by atomic mass </li></ul><ul><li>Step 3: Add totals for each element </li></ul>
  19. 20. EXAMPLES <ul><li>Find Molar mass for NaOH </li></ul><ul><li>Na 1 X 23.00 =23.00 </li></ul><ul><li>O 1 X 16.00 =16.00 </li></ul><ul><li>H 1 X 1.01 = 1.01 </li></ul><ul><li>40.01 g </li></ul>
  20. 21. Find Molar Mass of HC 2 H 3 O 2 <ul><li>H 4 x 1.01 = 4.04 </li></ul><ul><li>C 2 x 12.01 = 24.02 </li></ul><ul><li>O 2 x 16.00 = 32.00 </li></ul><ul><li>60.06 g </li></ul>
  21. 22. ON YOUR OWN <ul><li>Find the molar mass of the following: </li></ul><ul><ul><li>1. HCl </li></ul></ul><ul><ul><li>2. H 2 O </li></ul></ul><ul><ul><li>3. Al 2 (CO 3 ) 3 </li></ul></ul>
  22. 23. ANSWERS <ul><li>1. H 1 x 1.01 = 1.01 </li></ul><ul><ul><li>Cl 1 x 35.45 = 35.45 </li></ul></ul><ul><ul><li>36.46 g </li></ul></ul><ul><li>2. H 2 x 1.01 = 2.02 </li></ul><ul><ul><li>O 1 x 16.00 = 16.00 </li></ul></ul><ul><ul><li>18.02 g </li></ul></ul><ul><li>3. Al 2 x 26.98 = 53.96 </li></ul><ul><ul><li>C 3 x 12.01 = 36.03 </li></ul></ul><ul><ul><li>O 9 x 16.00 = 144.00 </li></ul></ul><ul><ul><li>233.99 g </li></ul></ul>
  23. 24. Homework <ul><li>Page 239 </li></ul><ul><li>#1 a,b,c,d,e,f </li></ul><ul><li>#2 a,b,c,d,e,f,g,h </li></ul><ul><li>Yes, this is section 2. We are covering the mole out of order. </li></ul><ul><li>Bring your book and a calculator to class everyday. This is a course requirement. </li></ul>