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Molar Conversions

The Mole. Molar Conversions. VERY. A large amount!!!!. A. What is the Mole?. A counting number (like a dozen) Avogadro’s number 1 mol = 6.02  10 23 particles (atoms, molecules, or formula units). A. What is the Mole?. HOW LARGE IS IT???.

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Molar Conversions

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  1. The Mole Molar Conversions

  2. VERY A large amount!!!! A. What is the Mole? • A counting number (like a dozen) • Avogadro’s number • 1 mol = 6.02  1023 particles (atoms, molecules, or formula units)

  3. A. What is the Mole? HOW LARGE IS IT??? • 1 mole of pennies would cover the Earth 1/4 mile deep! • 1 mole of hockey pucks would equal the mass of the moon! • 1 mole of basketballs would fill a bag the size of the earth!

  4. B. Molar Mass • Mass of 1 mole of an element or compound. • Molar Mass is equal to atomic mass, but the unit for molar mass is grams/mole (g/mol)

  5. B. Molar Mass Examples • Use Four Sig Figs • carbon • aluminum • zinc 12.01 g/mol 26.98 g/mol 65.39 g/mol

  6. B. Molar Mass Examples • water • sodium chloride • H2O • 2(1.008) + 16.00 = 18.02 g/mol • NaCl • 22.99 + 35.45 = 58.44 g/mol

  7. B. Molar Mass Examples • sodium bicarbonate • sucrose • NaHCO3 • 22.99 + 1.01 + 12.01 + 3(16.00) = 84.01 g/mol • C12H22O11 • 12(12.01) + 22(1.01) + 11(16.00) = 342.34 g/mol

  8. Molar Mass w/s

  9. Agenda 11/11 • Mole Candy Lab • Molar Conversions Notes Hw: Mole Candy Post lab and Molar Conversions w/s

  10. MASS IN GRAMS MOLES NUMBER OF PARTICLES (atoms, molecules or formula units) C. Molar Conversions molar mass 6.02  1023 (g/mol) (particles/mol)

  11. C. Molar Conversion Examples • How many moles of carbon are in 26 g of carbon? 26 g C 1 mol C 12.01 g C = 2.2 mol C

  12. C. Molar Conversion Examples • How many molecules are in 2.50 moles of C12H22O11? 6.02  1023 molecules 1 mol 2.50 mol = 1.51  1024 molecules C12H22O11

  13. C. Molar Conversion Examples • Find the mass of 2.1  1024 molecules of NaHCO3. 2.1  1024 molecules 1 mol 6.02  1023 molecules 84.01 g 1 mol = 290 g NaHCO3

  14. C. Molar Conversion Examples • Find the mass of 1.00 Fe atom • 1 mole Fe = 55.85g • 1 mole Fe = 6.02 x 1023 atom • 1.00 atom Fe55.85 g 1 mole 1 mole 6.02 x 1023 atoms = 9.28 x 10-23 g/atom

  15. C. Molar Conversions • How many Oxygenatoms are there in 50.25 g of CaCO3? 50.25g CaCO3 6.02 x 1023atoms O 1 mol CaCO3 3 mol O 1 mol CaCO3 100.09 g 1 mol O = 9.075 x 1023 atoms

  16. The Mole-Volume Relationship

  17. The Volume of a Gas • Many of the chemicals we deal with are gases • They are difficult to mass • Two things effect the volume of a gas • Temperature and pressure • We need to compare gases at the same temperature and pressure

  18. Standard Temperature and Pressure (STP) • 0°C and 1 atmosphere (atm) of pressure • At STP, 1 mole of any gas occupies 22.4 L • Called the molar volume • 1 mole = 22.4 L of any gas at STP

  19. Practice examples • What is the volume of 4.59 mole of CO2 gas at STP? • How many moles is 5.67 L of O2 at STP? • What is the volume of 8.8 g of CH4 gas at STP?

  20. Molarity –Molar Volume of… Solutions! • Molarity = moles of solute liter of solution • M= n V • n = moles of solute • V = volume (L) of solution • Note: it’s liters of solution, not liters of solvent

  21. Molarity Examples • How many moles of NaCl are in 0.65 L of 1.20 M NaCl solution? • 0.78 moles NaCl • How many moles of HCl are there in 2.43 L of 0.25 M HCl (aq)? • 0.61 moles HCl

  22. Molarity Examples • How many grams of HF are there in 0.55 L of 1.5 M HF solution? • 17 g • How many grams of HNO3 are there in 2.50 L of 5.00 M HNO3 (aq)? • 788 g

  23. Molarity Examples • Calculate the molarity of a solution made by dissolving 23.4 g of sodium sulfate in 125 ml of solution (hint: you need to find the formula of sodium sulfate) • 23.4 g Na2SO4  0.165 mol • 125 ml  0.125 L • M = mol / L • M = 0.165mol / 0.125 L • 1.32 M

  24. Molarity Examples • Calculate the molarity of a solution made by dissolving 5.00 g of C6H12O6 in enough water to make 100.0 ml of solution • 0.280 M

  25. Molarity Examples • How many grams of Na2SO4 are required to make 0.350 L of a 0.500 M solution of Na2SO4? • 24.9 g Na2SO4

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