SI unit for the amount of a substance A system of counting atoms/ molecules ◦ Much like we count eggs in dozens
Named after Amedeo Avogadro 6.02x10 23 Number of atoms/ molecules in one mole of substance If every person living on Earth worked to count the atoms in one mole of an element, and if each person counted continuously at a rate of one atom per second, it would take about 4 million years for all the atoms to be counted.
The mass of a substance that contains exactly 6.02x10 23 particles of that substance. Numerical value is the same as the formula mass ◦ Unit: g/mol ◦ Ex: mol mass of C= 12.01g/mol; mol mass of O= 16.00g/mol
# of mol= g x 1 _ molar mass Ex: 24.02 g of Carbon= ? mol 24.02g x 1mol = 2.00 mol 12.01g
64.14g of sulfur is equal to how many moles? A sample is No has a mass of 90g. How many moles is this?
# of g= mol x molar mass Ex: 1.5 mol of He= ? g 1.5mol x 4.00g = 6.0 g He 1 mol
What is the mass of 2.5 mol of CO 2 ? What is the mass of 5 mol of Ne?