2 Mole Facts6.02 X 1023 Pennies: Would make at least 7 stacks that would reach the moon.6.02 X 1023 Watermelon Seeds: Would be found inside a melon slightly larger than the moon.6.02 X 1023 Blood Cells: Would be more than the total number of blood cells found in every human on earth.1 Liter bottle of Water contains 55.5 moles H20
3 A Brief History…Amadeo Avogadro was an Italian physics professor who proposed in 1811 that equal volumes of different gases at the same temperature contain equal numbers of moleculesJosef Loschmidt, an Austrian high school teacher,in 1865, calculated the number of molecules in one cm3 of gaseous substance to be somewhere around 2.6 x 1019J.Perrin (1908) estimated the value to be between 6.5 x 1023 and 6.9 x 1023Rutherford and Geiger used radioactive methods: 6.2 x 1023The best modern values for what we now call "Avogadro's Number" are the result of the x-ray diffraction measurement of lattice distances in metals and salts.
4 Definition of a MoleThe amount of atoms in 12.0 grams of Carbon 12 (6.02 x 1023 atoms known as Avogadro’s number).A sample of any element with a mass equal to that element's atomic weight (in grams) will contain precisely one mole of atoms (6.02 x 1023 atoms).
5 How do we determine MOLAR MASS? Molar Mass: Mass in grams of one mole of that substanceWhat is the molar mass of H2O?2 Hydrogen atoms: 2 x 1g = 2g1 Oxygen atom: 1x 16g = 16g1 mole H2O = 18gWhat is the molar mass of CO2?Fe2O3?
6 Why is the mole an important unit in chemistry? Atoms and molecules react with one another particle by particleThe mole is the translation factor between weights and numbers of particles
7 How do we convert mass to particles? How many moles in 10 g of O2?10g O2 x 1 mole32g = molHow many molecules in 55 g of H2O?55g H2O x 1mole x 6.02 • 102318g mole= 18.4 • = 1.84 • 1024 molecules