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Introduction to the Mole and Molar Mass. Purpose. At the completion of this unit students will Have a conceptual understanding of the mole as the method of “counting” items and finding the mass of items that can’t be seen.
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Purpose At the completion of this unit students will • Have a conceptual understanding of the mole as the method of “counting” items and finding the mass of items that can’t be seen. • Be able to calculate the number of items (molecules, atoms, ions, and formula units) if given the number of moles. • Be able to calculate the number of moles if given the number of items. • Be able to calculate the mass of a sample if given the number of moles in a sample. • Be able to calculate the number of moles in a sample if given the mass of a sample. • Be able to prepare a sample containing a given number of moles. • Be able to determine the molar mass of a compound.
Background • When you buy eggs you usually ask for a _______ eggs. • You know that one dozen of any item is ______. Dozen 12
Paper • Paper is packaged by a ream. • A ream of paper has 500 sheets. • Why is it useful to use units like a dozen or a ream?
What determines how many items should make up a particular unit?
If you were asked to design a new unit to count something, what would you consider when choosing how many items should be included in your new counting unit?
ANALYSIS AND INTERPRETATION • As you know, a dozen represents 12 items. • What if I decided to make a new counting unit? I called this unit a DART. Each dart is • _____ items. 1 Dart = 4 items, just like 1 Dozen = 12 items 4
3. A DART of molecules of water has ____ molecules of water. 4
5. A DART of atoms of iron has _____ atoms of iron. 4 26 Fe 55.85
6. A DART of formula units of salt has _______ formula units of salt. 4
15. How many atoms of silver are in 20 DARTS? _______ 80 47 Ag 107.9
Write the directions for finding the number of items if given the number of DARTS
4 17. How many DARTS are 16 Hershey’s Kisses? ______
25 18. How many DARTS are 100 pretzels? ____
100 19. How many DARTS are 400 Starbursts? ____
¼ 0.25 20. How many DARTS is 1 orange? ________ (Write a fraction or a decimal.)
0.5 21. How many DARTS are 2 caramels? _____
Write your own directions for finding the number of DARTS given the number of pieces
DARTS • DART of molecules of water would be too small to see. • Scientists had to select a bigger unit for counting molecules of substances. • The unit scientists use is called a MOLE.
One MOLE of anything has 602,200,000,000,000,000,000,000items.
AVOGADRO’S NUMBER • 6.02 x 1023 • One MOLE of anything has 6.02 x 1023 items.
VERY A large amount!!!! A. What is the Mole? • A counting number (like a dozen) • Avogadro’s number (NA) • 1 mol = 6.02 1023 items
A. What is the Mole? HOW LARGE IS IT??? • 1 mole of hockey pucks would equal the mass of the moon! • 1 mole of pennies would cover the Earth 1/4 mile deep! • 1 mole of basketballs would fill a bag the size of the earth!
28. How many Hershey’s Kisses make up 1 MOLE? 6.02 x 1023
6.02 x 1023 A mole of Caramels is _____ caramels.
A mole of Jolly Ranchers is ______Jolly Ranchers 6.02 x 1023
A mole of silver atoms is _______ atoms of silver. 6.02 x 1023 47 Ag 107.9
29. How many caramels make up 10 MOLES? 10 [6.02 x 1023] 60.2 x 1023 Which is 6.02 x 1024
30. Find the number of Jolly Ranchers in 4 MOLES. 4 [6.02 x 1023] = 2.408 x 1024
31. Find the number of atoms of sodium in 2 MOLES. 2[6.02 x 1023]= 1.20 x 1024 11Na 22.99
32. Find the number of molecules of water in 6 MOLES. 6[6.02 x 1023]= 3.61 x 1024
33. Find the number of caramels in 0.5 MOLES. .5[6.02 x 1023 ]= 3.011 x 1023
34. How many moles of caramels is 6.02x1023 of caramels? ___ 1
35. How many moles of Starbursts is 6.02x1023 of Starbursts? ___ 1
36. How many moles of Gobstoppers is 12.04x1023 of Gobstoppers? ___ 2 12.04 x 1023 = 2 6.022 x 1023
37. How many atoms of potassium make up one MOLE? 6.02 x 1023 19 K 39.10
38. How many atoms of potassium make up 2 MOLES? 2[6.02 x 1023 ] 12.044 x 1023 1.20 x 1024 19 K 39.10
39. How many molecules of water make up 1 MOLE? 6.02 x 1023
40. How many molecules of water make up 5 MOLES? 5[6.02 x 1023 ]= 3.01 x 1024
41. How many moles are 6.022 x 1023 atoms of sodium? _____ 1