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WHAT IS A MOLE? x 10 23

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Mole Facts 6.02 X Pennies: Would make at least 7 stacks that would reach the moon X Pennies: Would make at least 7 stacks that would reach the moon X Watermelon Seeds: Would be found inside a melon slightly larger than the moon X Watermelon Seeds: Would be found inside a melon slightly larger than the moon X Blood Cells: Would be more than the total number of blood cells found in every human on earth X 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 H Liter bottle of Water contains 55.5 moles H 2 0

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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 molecules 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 molecules Josef Loschmidt, an Austrian high school teacher,in 1865, calculated the number of molecules in one cm 3 of gaseous substance to be somewhere around 2.6 x Josef Loschmidt, an Austrian high school teacher,in 1865, calculated the number of molecules in one cm 3 of gaseous substance to be somewhere around 2.6 x J.Perrin (1908) estimated the value to be between 6.5 x and 6.9 x J.Perrin (1908) estimated the value to be between 6.5 x and 6.9 x Rutherford and Geiger used radioactive methods: 6.2 x Rutherford and Geiger used radioactive methods: 6.2 x The 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. The 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.

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Definition of a Mole The amount of atoms in 12.0 grams of Carbon 12 (6.02 x 1023 atoms known as Avogadros 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).

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How do we determine MOLAR MASS? Molar Mass: Mass in grams of one mole of that substance Molar Mass: Mass in grams of one mole of that substance What is the molar mass of H 2 O? What is the molar mass of H 2 O? 2 Hydrogen atoms: 2 x 1g = 2g 1 Oxygen atom: 1x 16g = 16g 1 mole H 2 O = 18g What is the molar mass of CO 2 ? Fe 2 O 3 ?

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Why is the mole an important unit in chemistry? Atoms and molecules react with one another particle by particle The mole is the translation factor between weights and numbers of particles

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How do we convert mass to particles? How many moles in 10 g of O 2 ? 10g O 2 x 1 mole 32g = mol 32g = mol How many molecules in 55 g of H 2 O? 55g H 2 O x 1mole x g 1mole 18g 1mole = = molecules = = molecules

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