Relating Mass to Number of Atoms The Mole!
Mole is a quantity Mole is the amount of substance that has as many particles as exactly 12 g of carbon-12 Moles are essential to understand chemical reactions and stoichiometry
What is the mass in grams of 3.50 mole of the element copper?
A chemist produced 11.9 g of aluminum. How many moles of aluminum were produced?
Avogadro’s number tells how many particles are in a mole Experimentally determined to be x particles/mole We use: x particles/mole
Mass of one mole of a pure substance Since amu are defined based on carbon-12 and so are moles, one mole of an element has the average atomic mass in grams Usually written in units of g/mole Example: molar mass of Fe is g/mole
Molar mass can be used to convert from grams to moles and vice versa Sample problem 3-2 p 82 Sample problem 3-3 p 83
Since we know the number of particles in one mole, we can use it with moles or mass Sample problem 3-4 p 84 ◦ How many moles of silver are in 3.01 x atoms of silver? Sample problem 3-5 p 84 ◦ What is the mass in grams of 1.20 x 10 8 atoms of copper?