1. Moles In Chemistry a mole is defined as 6.022x10 23 particles of a substance. Moles are not to be confused with this happy individual. This is a very special and important measured number known as Avogadro’s Number. Dozen = 12units Mole = 6.022x10 23 units Atoms are too small to count so we use moles in chemical reactions.

2. 2Mg + O 2  2MgO 2 moles of Magnesium react with one mole of Diatomic Oxygen to yield 2moles of magnesium Oxide When we want to create something new in a chemical reaction we need to know how much of each to mix together to yield what we want. We can’t count atoms as they are too small so we use moles which can be converted to grams very easily.

3. Moles use mass as a means of counting atoms! 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 26 Fe IRON 55.85 The atomic mass of iron is 55.85 Amus. This number also represents the molar mass of Iron. Iron has a molar mass of 55.85 grams per mole. This means one mole or 6.022x10 23 atoms of iron will weigh 55.85g.

4. MOLAR MASS 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 26 Fe IRON 55.85 This is the molar mass of any single element Unit: g/mol

5. Gold Mercury Silver Oxygen Sulfur Hydrogen 79 Au Gold 196.96 80 Hg Mercury 200.59 47 Ag Silver 107.9 8 O Oxygen 16 1 H Hydrogen 1 197g/mol 200.6g/mol 39.95g/mol 32g/mol (diatomic) 32.07g/mol 2g/mol (diatomic) How many atoms are there in a mole of gold atoms? How many atoms are there in a mole of silver atoms? 1 mol = 6.022 x10 23 units

6. If I asked you for one mole of iron, how would you do it? 26 Fe Iron 55.85 Weigh out 55.85g of iron How many atoms of iron is that? 1 Mole = 6.022x10 23 units

7. Give me 3.63 moles of iron? If I asked you for 3.63 moles of iron, how would you do it? Give me 3.63 moles of H 2 0? 26 Fe Iron 55.85

8. What is the Molar Mass of H 2 0 O HH I’m asking for the mass of one dozen of water. A dozen Oxygen = 16g and dozen hydrogen = 1g. We would have a dozen of Oxygen We would have a dozen of Hydrogen We would have another dozen of Hydrogen 8 O Oxygen 16 1 H Hydrogen 1 16g/doz 1g/doz 1 H Hydrogen 1 1g/doz ++= 18g/doz

9. What is the Molar Mass of H 2 0 O HH One molecule of H 2 0 I’m asking for the mass of one mole of water. A mole of H 2 0 would consist of 6.022x10 23 molecules. We would have a mole of Oxygen We would have a mole of Hydrogen We would have another mole of Hydrogen 8 O Oxygen 16 1 H Hydrogen 1 16g/mol 1g/mol 1 H Hydrogen 1 1g/mol ++= 18g/mol

10. What is the Molar Mass of CO 2 ? 8 O Oxygen 16 6 C Carbon 12 Step1: Count Atoms CO 2 1 Carbon 2 Oxygen Step 2: Add the molar masses (in g/mol) of the constituent atoms. 12g/mol + 2(16g/mol) = 44g/mol

11. Magnesium Nitrate: Mg(NO 3 ) 2 Step1: Count Atoms Step 2: Add the molar masses (g/mol) of the constituent atoms. 8 O Oxygen 16 7 N Nitrogen 14.01 12 Mg Magnesium 24.3 1 Mg2 N6 O 24.3g/mol2(14.01g/mol)6(16g/mol) 24.3g/mol + 2(14.01g/mol) + 6(16g/mol) = 148.3g/mol

12. Molar Mass of Sucrose C 12 H 22 O 11 8 O Oxygen 16 6 C Carbon 12 1 H Hydrogen 1 12 C22 H 11 O Step1: Count Atoms Step 2: Add the molar masses (g/mol) of the constituent atoms. 12(12g/mol)22(1g/mol)11(16g/mol) 12(12g/mol) + 22(1g/mol) + 11(16g/mol) = 342.3g/mol

13. 2g What will 3 blocks of purple awesomeness weigh?

14. x = Unit you want to change Unit you are changing into Conversion Factor 1.Start with the unit you want to change. 2.Multiply it by a blank fraction. 3.The unit you want to change goes in the denominator. 4.The unit you want to convert into goes into the numerator and answer. 5.Insert the values for your conversion factor. 6.Solve the problem. Convert 3.5mol Fe into gram. 26 Fe Iron 55.85

15. MOLES LITERS ATOMS GRAMS 1 mole = 6.022x10 23 units Gas at STP 22.4L = 1mole Molar mass = atomic mass 1 mole = 6.022x10 23 units Gas at STP 22.4L = 1mole Molar mass = atomic mass 47 Ag Silver 107.9 How many moles is 200g Ag? How many grams is 3.5mol Hg? 80 Hg Mercury 200.59 How many atoms are there in 2.5mol Hg? How many moles are there in 5x10 30 atoms Ag? How many moles are there in 400L of air at STP? How many liters is 6 moles of CO 2 gas at STP? Or molecules

16. MOLES LITERS ATOMS GRAMS 1 mole = 6.022x10 23 units Gas at STP 22.4L = 1mole Molar mass = atomic mass 1 mole = 6.022x10 23 units Gas at STP 22.4L = 1mole Molar mass = atomic mass 11 Na Sodium 23 17 Cl Chlorine 35.5 How many atoms are there in 230g of Sodium? How many moles is 440g NaCl? grams  moles  atoms 10 mol Na  atoms Or molecules How much would a trillion atoms of sodium weigh? grams  moles  atoms 0.0000000000391g Na

17. Calculating Gas Density What is the density of ammonia gas, NH 3, at STP? First we need the molar mass for ammonia; 14.01 + 3(1.01) = 17.04 g/mol The molar volume NH 3 at STP is 22.4 L/mol. Density is mass/volume: = 0.761 g/L 17.04 g/mol 22.4 L/mol

18. Calculating Gas Density What is the density of, O 2, at STP? First we need the molar mass for O 2 ; 2(16g/mol) = 32 g/mol The molar volume O 2 at STP is 22.4 L/mol. Density is mass/volume: = 1.4 g/L 32 g/mol 22.4 L/mol

19. Activity: 1 Cup of Water ~236ml What is the molar mass of H 2 O? How many grams is the cup of water? How many moles is it? How many molecules of H 2 O are there? How many total atoms? All you need for this is a periodic table and a calculator

20. Bling Bling: if I were to give each of you one atom of gold for every second that has elapsed since the Dinosaur’s went extinct 65 million years ago, how much gold would you have?