1 / 20

Introducing the mole

Introducing the mole. Counting units. 1 pair = 2. 1 dozen = 12. 1 score = 20. 1 gross = 144. 1 ream = 500. But for counting atoms?. Consider… The period at the end of a sentence contains about 4 billion atoms.

long
Download Presentation

Introducing the mole

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. Introducing the mole

  2. Counting units • 1 pair = 2 • 1 dozen = 12 • 1 score = 20 • 1 gross = 144 • 1 ream = 500

  3. But for counting atoms? • Consider… • The period at the end of a sentence contains about 4 billion atoms. • There are more atoms in a glass of water than glasses of water in all the oceans in the world . • The counting unit for atoms has to be BIG!

  4. We call this unit… • A mole!

  5. A mole? • Simply a counting unit. 6.02x1023 More specifically: 602,214,141,070,409,084,099,072

  6. Representative Particles • A counting unit counts the representative particles. • These particles can be atoms, or molecules, or ionic compounds, or elephants, or anything. • One mole of representative particles is 6.02E23 of those particles.

  7. Lorenzo Romano Amedeo CarloAvogadro 1776-1856 Professor of Physics, Turin Italy Different gases at same pressure and temperature have different weights Hypothesized that this was because of differences in weight of molecules Who thought this up?

  8. Avogadro’s Number • 6.02x1023is Avogadro’s number • A mole is a counting unit, made of Avogadro’s number of something, or 6.02x1023 somethings

  9. Examples 6.02x1023 jellybeans. • A mole of jellybeans is … • Half a mole of Sarah Palins is …. 3.01x1023 Sarah Palins • 2 moles of cats is … 1.20x1024 cats.

  10. And… • 1 mole of molecules is … 6.02x1023 molecules. • Now you … • 4 moles of water molecules is … = 2.41x1024 molecules

  11. Perspective • One mole of marbles would cover the entire Earth (oceans included) for a depth of three miles. • The Earth’s population is 6.6 billion people. It would take 9.1x1013 Earths to make a mole of people.

  12. Try it • A ream of paper contains 500 sheets. A box of copy paper contains 10 reams. • In order to get a mole of sheets of paper, how many boxes would be required? • How many reams would be required?

  13. Moles of elements • How do we know how many moles of an element are present? • We need to know the molar mass. • Where do we find the molar mass? • From the periodic table.

  14. Finding the molar mass • Molar mass is different for each element. • Molar mass is found with each element on the periodic table. This number is molar mass. 29 Cu 63.546 1 mole of copper weighs 63.546 grams so… 63.546 grams of copper contains 6.02x1023 atoms

  15. Examples 19 K 39.098 6 C 12.011 1 H 1.008 82 Pb 207.2

  16. More examples • 1 mole of Strontium (Sr) = 87.62 grams • 2 moles of Plutonium (Pu) = 488.128 grams • 118.710 grams of Tin (Sn) = 1 mole • 54 grams of Silver (Ag) = ??

  17. But what about compounds? • The sum of its parts. • Consider… Titanium Dioxide • TiO2 The parts… Ti : 47.867 g/mol x 1 O : 15.999 g/mol x 2 The sum… = 47.867 = 31.998 79.865 g/mol

  18. Another example • Ammonium Carbonate • (NH4)2CO3 The parts… N : 14.00 g/mol x H : 1.01 g/mol x C : 12.01 g/mol x O : 15.99 g/mol x The sum… 2 = 28.00 8 = 8.08 1 = 12.01 3 = 47.97 96.06 g/mol

  19. 6.02E23 atoms 1 mole And now… a little practice 1. Find the number of atoms of phosphorus (P) in 3.44 moles of phosphorus. 3.44 moles x = 2.071E24 atoms

  20. 58.933 g1 mole One more… 2. What is the mass of 0.38 moles of cobalt (Co)? 0.38 moles x = 22.395 g 27 Co 58.933

More Related