Chem Ch 9 Notes• 9.1 Stoichiometry- calculation of quantities  in chemical reactions• From the coefficients in a BALANCED ...
• 3. Mass- Obeys Law of Conservation of    Mass    • 1 mol N2 = 28.0 g    • +3 mol H2 = 6.0 g    • 2 mol NH3 = 34.0 g•   4...
• Mole-Mole calculations  • N2+3H2  2NH3  • 1mol N2     1moleN2    2 mol NH3    3 mol H2    2mol NH3 3 mol H2  These are ...
• Mass:Mass• 1. Convert mass to moles (1mol/ g)• 2. Convert moles of what you have to moles  of what you want• 3. Convert ...
• How many moles O2 are produced when 29.2 g H2O decomposed into O2 & H2?• Assuming STP, how many L O2 are needed to produ...
• Use ratios from coefficients b/c the  volumes relate from 22.4L=1mol   • 2NO(g) + O2 (g)  2 NO2(g)  • How many mL NO2 a...
• Limiting reactant & % Yield• Limiting Reagent- determines amt. Of  product formed, runs out 1st• Steps: (if given 2 reac...
• 2 Na(s) + Cl2 (g)  2NaCl (s)• Suppose 8.70 mol Na react w/3.20 mol Cl2.   • What is limiting reactant?   • How many mol...
• 2Cu (s) + S (s)  Cu2S(s)   • What is the limiting reactant when 80.0    g Cu reacts with 25.0 g S?  • How many g Cu2S c...
• % yield- measures the efficiency of reaction  • Normally can’t be larger than 100%  • Most are less than 100 % b/c:     ...
• Actual yield- amt. of product formed in lab• Theoretical yield- amt. product that could  be formed from calculations• % ...
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Ch 9 power point notes

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Ch 9 power point notes

  1. 1. Chem Ch 9 Notes• 9.1 Stoichiometry- calculation of quantities in chemical reactions• From the coefficients in a BALANCED equation you can get: • N2+3H2 2NH3• 1. # particles (molecules, formula units, atoms) • 1 molecule N2: 3 molecules H2 : 2 molecules NH3• 2. # moles • 1 mole N2: 3 mole H2 : 2 mole NH3
  2. 2. • 3. Mass- Obeys Law of Conservation of Mass • 1 mol N2 = 28.0 g • +3 mol H2 = 6.0 g • 2 mol NH3 = 34.0 g• 4. Volume- GASES at STP 1 mol= 22.4L• 3 mol H2 = 3(22.4)=67.2L• 1 mol N2 = 1(22.4) = 22.4 L• 2 mol NH3 = 2(22.4) = 44.8 L• Notice that the number of atoms & mass are always conserved, but the volume & molecules may not be!!
  3. 3. • Mole-Mole calculations • N2+3H2  2NH3 • 1mol N2 1moleN2 2 mol NH3 3 mol H2 2mol NH3 3 mol H2 These are your mole conversion factors How many moles of NH3 are in 0.60 mol N2?
  4. 4. • Mass:Mass• 1. Convert mass to moles (1mol/ g)• 2. Convert moles of what you have to moles of what you want• 3. Convert mol to mass ( g/1mol)• How many g NH3 are produced when 5.40 g of H2 react w/ excess N2?• For all problems• Convert to mol, use mol:mol, convert to wanted units
  5. 5. • How many moles O2 are produced when 29.2 g H2O decomposed into O2 & H2?• Assuming STP, how many L O2 are needed to produce 19.8 L SO3? • 2SO2(g) + O2(g)  2 SO3(g)
  6. 6. • Use ratios from coefficients b/c the volumes relate from 22.4L=1mol • 2NO(g) + O2 (g)  2 NO2(g) • How many mL NO2 are produced when 3.4mL O2 react with excess NO at STP? • 1mL O2=2 mL NO2=2 mL NO
  7. 7. • Limiting reactant & % Yield• Limiting Reagent- determines amt. Of product formed, runs out 1st• Steps: (if given 2 reactants) • 1. Solve for same product • 2. One w/least amount of product is limiting • 3. Other is excess (left over) • 4. Limiting determines the amount of product
  8. 8. • 2 Na(s) + Cl2 (g)  2NaCl (s)• Suppose 8.70 mol Na react w/3.20 mol Cl2. • What is limiting reactant? • How many moles of NaCl are produced? • How many g NaCl are produced? • How much of the excess reactant is left?
  9. 9. • 2Cu (s) + S (s)  Cu2S(s) • What is the limiting reactant when 80.0 g Cu reacts with 25.0 g S? • How many g Cu2S can be formed? • How much of the excess reactant is left?
  10. 10. • % yield- measures the efficiency of reaction • Normally can’t be larger than 100% • Most are less than 100 % b/c: • Reactions don’t go to completion • Impure reactants • Competing side reaction • Loss of product during transfer or filtration • Human error (bad measurement, miscalculation)
  11. 11. • Actual yield- amt. of product formed in lab• Theoretical yield- amt. product that could be formed from calculations• % Yield: actual yield X 100 theoretical yield• CaCO3 (s)  CaO (s) + CO2 (g) • What is the theoretical yield of CaO if 24.8 g CaCO3 is heated? • What is the % yield if 13.1 g CaO is produced?

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