The Mole and Molar Mass

The Mole 1 dozen = 12 eggs 1 ream = 500 sheets of paper 1 hat trick = 3 goals 1 mole = 6.022 x 1023 atoms (or ANYTHING!) Or 602,200,000,000,000,000,000,000 atoms Also known as “Avogadro’s number”

The Mole 1.0079 g of H contains 6.022 x 1023 atoms 12.011 g of C contains 6.022 x 1023 atoms 15.999 g of O contains 6.022 x 1023 atoms 196.97 g of Au contains 6.022 x 1023 atoms 40.078 g of Ca contains 6.022 x 1023 atoms See the pattern?

The Mole 6.022 x 1023 atoms (or molecules) / mol molar mass: the atomic weight (in grams) is the mass of one mole of that element We can also find the molar mass of compounds by ADDING the molar masses of each element Molar masses have units of g/mol Note: units on Avogadro’s # are 6.022 x 1023 atoms (or molecules) / mol

Molar Mass Example What is the molar mass of calcium hydroxide, Ca(OH)2?

Example How many moles does a 25.2 gram sample of CaCl2 contain?

Example How many moles of silver are equivalent to 2.888 x 1015 atoms?

Example What is the mass of 1.735 x 1020 magnesium atoms?