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Calculators, reference tables, notes. Get your thinking caps on!

OB: intro to STOICHIOMETRY Using ratios of balanced reactions to manipulate the chemical variables in these reactions. Calculators, reference tables, notes. Get your thinking caps on!. Hydrogen + oxygen makes water Skeleton: H 2 + O 2 H 2 O.

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Calculators, reference tables, notes. Get your thinking caps on!

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  1. OB: intro to STOICHIOMETRYUsing ratios of balanced reactions to manipulate the chemical variables in these reactions Calculators, reference tables, notes. Get your thinking caps on!

  2. Hydrogen + oxygen makes water Skeleton: H2 + O2 H2O

  3. Hydrogen + oxygen makes water Skeleton: H2 + O2 H2O Balanced: 2H2 + O2 2H2O

  4. Hydrogen + oxygen makes water Skeleton: H2 + O2 H2O Balanced: 2H2 + O2 2H2O # of atoms: four + two makes six

  5. Hydrogen + oxygen makes water Skeleton: H2 + O2 H2O Balanced: 2H2 + O2 2H2O # of atoms: four + two makes six # of molecules: two + one makes two

  6. Hydrogen + oxygen makes water Skeleton: H2 + O2 H2O Balanced: 2H2 + O2 2H2O # of atoms: four + two makes six # of molecules: two + one makes two AMU: 4 amu + 32 amu = 36 amu

  7. Hydrogen + oxygen makes water Skeleton: H2 + O2 H2O Balanced: 2H2 + O2 2H2O # of atoms: four + two makes six # of molecules: two + one makes two AMU: 4 amu + 32 amu = 36 amu Grams: 4 g + 32 g = 36 grams

  8. Hydrogen + oxygen makes water Skeleton: H2 + O2 H2O Balanced: 2H2 + O2 2H2O # of atoms: four + two makes six # of molecules: two + one makes two AMU: 4 amu + 32 amu = 36 amu Grams: 4 g + 32 g = 36 grams # of MOLES: 2 moles + 1 mole = 2 moles

  9. For this reaction, the number of MOLES is 2 moles + 1 mole = 2 moles The mole ratio for this reaction is 2:1:2 This is like the “recipe” for the reaction.

  10. For every single chemical reaction that’s balanced, we can determine the “mole ratio”, or ratio of moles to moles to moles for that reaction. What’s the mole ratio for this? 4Al + 3O2 2Al2O3

  11. For every single chemical reaction that’s balanced, we can determine the “mole ratio”, or ratio of moles to moles to moles for that reaction. What’s the mole ratio for this? 4Al + 3O2 2Al2O3 That would be 4:3:2. It takes 4 moles of aluminum to react with three moles of oxygen, which forms two molesof aluminum oxide.

  12. To make brownies you use 1 box mix, 3 eggs, 1 cup water, and ½ cup oil. The “recipe” ratio is 1:3:1:½ How many eggs needed for a double batch?

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  14. 2H2 + O2 2H2O This has a 2:1:2 mole ratio. If you had 9.0 moles of hydrogen, how many moles of oxygen are required to complete this reaction? (hint, let’s use proportions)

  15. 2H2 + O2 2H2O This has a 2:1:2 mole ratio. If you had 9.0 moles of hydrogen, how many moles of oxygen are required to complete this reaction? 2x = 9.0 X = 4.5 moles oxygen H22O2 1 9.0x MR =

  16. THINK: Could you convert the 4.5 moles oxygen into grams? Could you covert it into liters of gas (at STP)? How about particles (if you really had to)? Using this mole ratio provided by every single balanced chemical reaction, we can use that ratio to “play” with every equation and do lots of conversions to it. This is Stoichiometry, the math manipulation of balanced reactions by conversions.

  17. Not long after the mole islands were found, just to the east, a new set of islands were found. Chemists, not being that creative, named them this way: Volume Island II Volume Island Mole Island II Mole Island Mass Island II Particle Island II Mass Island Particle Island

  18. Simple new names, but not connected together. So they started digging… Volume Island II Volume Island Mole Island II Mole Island Mass Island II Particle Island II Mass Island Particle Island

  19. Simple new names, but not connected together. So they started digging A TUNNEL Volume Island II Volume Island Mole Ratio Tunnel Mole Island II Mole Island Mass Island II Particle Island II Mass Island Particle Island

  20. This bigger map shows all the math conversions for all Stoichiometry. The same “tolls” or equalities apply on both sides of the map. So, how many grams of oxygen are required to completely react with 50.0 grams of hydrogen? Let’s look over the map, figure out where we are, and where we’re going.

  21. This bigger map shows all the math conversions for all Stoichiometry. The same “tolls” or equalities apply on both sides of the map. So, how many grams of oxygen are required to completely react with 50.0 grams of hydrogen? Let’s look over the map, figure out where we are, and where we’re going. 1 mole H22g H2 50.0 g H21 x = 25.0 moles H2

  22. How many grams of oxygen are required to completely react with 50.0 grams of hydrogen? 1 mole H22g H2 50.0 g H21 x = 25.0 moles H2 2x = 25.0 moles x = 12.5 moles oxygen H2O2 225.0 1 x MR 12.5 moles O21 32 g O21 moles O2 x = 400. grams O2 Stoichiometry in three easy steps…

  23. Using the same reaction, how many liters of oxygen are required to completely react with 155 grams of hydrogen gas? Use the map, decide where you need to start, then where you want to go…

  24. Using the same reaction, how many liters of oxygen are required to completely react with 155 grams of hydrogen gas? 1 mole H22g H2 155 g H21 x = 77.5 moles H2 277.5 1 x 2x = 77.5 moles x = 38.8 moles oxygen MR H2O2 22.4 L O21 moles O2 38.8 moles O21 x = 869 liters oxygen Stoichiometry in three steps

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