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Stoichiometry Calculations

Stoichiometry Calculations. Coach Cox. Mole to Mole Conversions. Converting from moles of one substance in a chemical reaction to moles of another substance in a chemical reaction. Mole to Mole: Example 1.

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Stoichiometry Calculations

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  1. Stoichiometry Calculations Coach Cox

  2. Mole to Mole Conversions • Converting from moles of one substance in a chemical reaction to moles of another substance in a chemical reaction

  3. Mole to Mole: Example 1 • If you dropped 0.040 moles of potassium into a beaker of water, how many moles of hydrogenwould you produce? • Step 1: Write a balanced chemical equation. • ____K(s) + ____ H2O(l)  ____ KOH(aq) + ____ H2(g) • Step 2: Start with your known, and use Dimensional Analysis with the correct mole ratio from the balanced equation to find the unknown • - Draw your pathway!

  4. Mole to Mole: Example 1 Answer • Balanced Equation:2K(s) + 2H2O(l)  2KOH(aq) + 1 H2(g) • 1 mol H2 • Pathway: 0.040 mol K ------------------------------------> moles of H2 • 2 mol K • 0.040 mol K x 1 mol H2= .02 mol H2 produced • 2 mol K

  5. Mole to Mole: Example 2 • Using the same number of moles of potassium, how many moles of H2O will be used? • Balanced Equation: 2K(s) + 2 H2O(l)  2KOH(aq) + 1 H2(g) • Work out the question the exact same way you did Example 1!

  6. Mole to Mole: Example 2 Answer • Balanced Equation: 2K(s) + 2 H2O(l)  2KOH(aq) + 1 H2(g) • 2 molH2O • Pathway: 0.040 mol K ------------------------------------> moles of H2O • 2 mol K • 0.040 mol K x 2 molH2O = .04 molH2O will be used • 2 mol K

  7. Mole to Mole: Example 3 • One disadvantage of burning propane, C3H8, is that CO2 is produced as a product. The released CO2 increases the growing concentration of carbon dioxide in the atmosphere. How many moles of CO2 are produced when 10.45 moles of C3H8 is burned in a propane gas grill? • ___ C3H8(g) + ___ O2(g) ___ CO2(g) + ___ H2O(l) • Work it out the same way, balance the equation first!

  8. Mole to Mole: Example 3 Answer • Balanced Equation: 1C3H8(g) + 5O2(g) 3CO2(g) + 4H2O(g) • 3 molCO2 • Pathway: 10.45 mol C3H8------------------------------------> moles of CO21 molC3H8 • 10.45 molC3H8x 3 molCO2 = 31.35 molCO2will be produced • 1 molC3H8

  9. Mole to Mole: Example 4 • The reaction between methane and, CH4, and sulfur produces carbon disulfide, CS2, a liquid used in the production of cellophane. • ___CH4 + ___S8 ___CS2 + ___H2S • Balance the equation. • Calculate the moles of CS2 produced when 1.78 moles of S8 is consumed. • How many moles of H2S is produced during this same reaction?

  10. Mole to Mole: Example 4 Answer • a. Balanced Equation: 2 CH4 + 1 S8 2 CS2 + 4 H2S • b. 1.78 molS8x 2 molCS2= 3.56 molCS2will be produced • 1 molS8 • c. 1.78 mol S8 x 4 molH2S= 7.12 molH2S will be produced • 1 molS8

  11. Mole to Mass Conversions • Converting from moles of one substance in a chemical reaction to mass of another substance in a chemical reaction

  12. Mole to Mass Example 1 • Determine the mass of NaCl produced when 1.25 moles of chlorine gas reacts with sodium • Step 1: Write a balanced equation • ___ Cl2 + ___ Na  ___ NaCl • Step 2: Start with your known, and use Dimensional Analysis with the correct mole ratio from the balanced equation to find the unknown • - Draw your pathway!

  13. Mole to Mass: Example 1 Answer • Balanced Equation: 1Cl2 + 2Na  2NaCl • Pathway: 1.25 mol Cl2 ------------------------------------------> grams NaCl produced • 1.25 molCl2x 2 molNaCl x 58.443 g NaCl = 146.11 grams NaClproduced • 1 molCl2 1 molNaCl

  14. Mole to Mass Example 2 • Determine the mass of the sodium needed to complete this same reaction. • Balanced Equation:1 Cl2 + 2 Na  2NaCl • Work out the question the exact same way you did Example 1!

  15. Mole to Mass: Example 2 Answer • Balanced Equation: 1 Cl2 + 2 Na  2NaCl • Pathway: 1.25 mol Cl2 ------------------------------------------> grams Na needed • 1.25 mol Cl2 x 2 molNa x 22.990 g Na= 57.475 grams Na needed • 1 mol Cl2 1 molNa

  16. Mass to Mass conversions • Converting from the mass of one substance in a chemical reaction to the mass of another substance in a chemical reaction

  17. Mass to Mass conversions • EVERYTHING MUST GO THROUGH MOLES!!! • (MOLE TO MOLE conversions)

  18. Mass to Mass Example 1 • Determine the mass of H2O produced from the decomposition of 25.0 g of ammonium nitrate (NH4NO3) • Step 1: Write a balanced equation • ___ NH4NO3 ___ H2O + ___ N2O • Step 2: Start with your known, and use Dimensional Analysisto convert from: • a. mass of known to moles of known using the periodic table • b. moles of known to moles or unknown using the correct mole ratio moles to • mass of the unknown using the periodic table • - Draw your pathway!

  19. Mass to Mass: Example 1 Answer • Balanced Equation: 1NH4NO3 2H2O + 1N2O • Pathway: 25 g NH4NO3 ---------------------------------------> grams H2O produced • 25 g NH4NO3 x 1 molNH4NO3 x2 molH2Ox 18.015 g H2O= 97.829 g NH4NO3 1 molNH4NO3 1 molH2O • = 9.207 grams of H2O produced

  20. Mass to Mass Example 2 • Calculate the number of grams of NH3 produced by the reaction of 5.4 g of hydrogen with an excess of nitrogen • ___ N2(g) + ___ H2(g) ___ NH3(g)

  21. Mass to Mass: Example 2 Answer • Balanced Equation: 1N2(g) + 3H2(g) 2NH3(g) • Pathway: 5.4 g H2---------------------------------------> grams NH3produced • 5.4 g H2x 1 molH2x2 molNH3x 17.031 g NH3= 2.016 g H21 molH2 1 molNH3 • = 91.2375 grams of NH3produced

  22. Particles to particles conversions • Converting from the particles of one substance in a chemical reaction to the particles of another substance in a chemical reaction

  23. Particles to particles conversions • EVERYTHING MUST GO THROUGH MOLES!!! • (MOLE TO MOLE conversions)

  24. Particles to particles conversions: Example 1 • Sodium hydrogen carbonate decomposes with heat to produce carbon dioxide gas, water, and solid sodium carbonate. 2.2 x 1023 formula units of sodium hydrogen carbonate react to form ________ molecules of carbon dioxide. • ___ NaHCO3(s) ___ Na2CO3(s) + ___ CO2(g) + ___ H2O(g)

  25. Particles to particles conversions: Example 1Answer • Balanced Equation:2NaHCO3(s) 1Na2CO3(s) + 1CO2(g) + 1H2O(g) • Pathway: 2.2 x 1023fun NaHCO3---------------------------------------> molecules CO2 • 2.2 x 1023fun NaHCO3 x 1 molNaHCO3x 1 molCO2 x 6.02x1023 molecules CO2 = 6.02x1023 fun NaHCO32 molNaHCO3 1 molCO2 • = 1.1 x 1023 molecules of CO2produced

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