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The Mole. One mole contains as many entities as there are in 12 grams of Carbon. This number is 6.02 x 10 23 . This has been carefully measured over many decades. Mole= 6.02 x 10 23 representative particles of that substance. It is called Avogadro’s number.
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One mole contains as many entities as there are in 12 grams of Carbon. • This number is 6.02 x 1023. This has been carefully measured over many decades.
Mole= 6.02 x 1023 representative particles of that substance. • It is called Avogadro’s number. • Representative particles -what is present in a substance atoms, molecules, particles or formula units. • One mole of ANY specified entity contains 6.02 x 1023 of that entity
one mole of donuts= 6.02 x 1023 donuts • One mole of H2O = 6.02 x 1023 H2O • One mole of dogs= 6.02 x 1023 dogs
How many atoms or molecules? • Given moles just multiply by Avagadro’s number. Use conversion factors. • Example 1: .450 mole of Fe contains how many atoms? • .450 mol x (6.02 x 1023) atoms =2.71 x 1023atoms 1 mol
How many moles? • Given number of representative particles (atoms, molecules etc.) divide particles by Avagadro’s number. Use conversion factors. • Example 2: How many moles are in 1.20 x 1023 atoms? • 1.20 x 1023atoms x 1mol = .199 mol • 6.02 x 1023atoms
Moles to Grams 1.Determine how many moles in problem. 2. Calculate molar mass of substance. • Multiply by conversion factor. Example: How many grams are in .700 moles of Ag? .700 mol x 107.87g= 75.5 g 1 mol
Grams to Moles 1. Determine how many grams in problem 2.Calculate molar mass. 3. Divide grams by molar mass. Example: Convert 25.0 grams of K to moles. 25.0 g x 1 mol= .639 mol 39.10 g