2 The Mole Concept Avogadro’s Number = 6.022 x 1023 Objectives: To state the value of Avogadro’s number: x1023.To state the mass of Avogadro’s number of atoms for any element by referring to the periodic table.To relate the moles of a substance to the number of particles.Avogadro’s Number = x 1023
4 Chemical QuantitiesThere are terms used to equate a certain quantity of matterFor example 1 dozen = 12, 1 Ton = 2,000 LBs and 1 gross = 144.Before we get to the chemical terms lets convert between units we already know
5 For example – let’s say you want to buy some Bazooka Gum You could buy it by the piece from the deliYou could buy it by the box from ShopRiteYou could buy it by mass from the candy store
6 So, the different ways to measure Bazooka gum 1 dozen = 12 pieces1 dozen = 1.75 boxes1 dozen = 168 grams
7 Based on those conversions, I can determine how much Bazooka gum I have, regardless of how it is measured.I have 95 pieces of Bazooka gum, how many grams do I have?
8 I have 95 pieces of Bazooka gum, how many grams to I have?
9 Do-NowIf I have 2 stadiums how many baseball bats do I want to purchase?2 baseball players = 4 baseball bats1 stadium = 18 baseball players18 baseball players = 52 corn dogs
12 Chemical QuantitiesIn chemistry, there are many way to measure the amount of substanceThe count (quantity)The volume (how much space it takes up)The mass (the amount of matter)Knowing how the count, mass, and volume of an item relate to a common unit allows you to convert among these units.
13 In chemistry, we do not use a dozen. Since atoms are so small, we need a quantity with a larger amountWe use the mole (mol)1 mole = X 1023 representative particles (atoms, molecules, formula units)It is known as Avogadro’s numberAmedeo Avogadro
14 Amedeo AvogadroAn Italian chemist whose important contributions was his resolution of the confusion surrounding atoms and molecules. Avogadro believed that particles could be composed of molecules and that molecules could be composed of still simpler units, atoms. The number of molecules in a mole (one gram molecular weight) was termed Avogadro's number
15 We usually are dealing with three types of representative particles MoleculesH2O and H2 are molecules, covalently bondedAtomsAl and Na are atoms, not bondedFormula unitsCaCl2 and NaOH are formula units, ionicly bonded
16 1 mole of any representative particle is always 6.02 X 1023 Using this value we can convert between moles and atoms/ molecules/ formula units
17 For example: If a sample contains 0 For example: If a sample contains mol of O2, how many representative particles are present?0.476 mol O2 x (6.022 x 1023 particles/1 mol O2) = x 1023
18 For example: If a sample contains 5 For example: If a sample contains X 1021 atoms of aluminum, how many moles are present?