Measuring concentration

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Measuring concentration

  1. 1. Measuring Concentration Molarity
  2. 2. Molarity (M) <ul><li>A measurement of the concentration of a solution </li></ul><ul><li>Molarity (M) is equal to the moles of solute (n) per liter of solution M = n / V = mol / L  </li></ul><ul><li>Molarity (M ) = moles of solute </li></ul><ul><li> 1 liter solution </li></ul>
  3. 3. Units of Molarity <ul><li>2.0 M HCl = 2.0 moles HCl </li></ul><ul><li> 1 L HCl solution </li></ul><ul><li>6.0 M HCl = 6.0 moles HCl </li></ul><ul><li> 1 L HCl solution </li></ul>
  4. 4. <ul><li>A KOH solution with a volume of 400 mL contains 2 mole KOH. What is the molarity of the solution? </li></ul>
  5. 5. <ul><li>A KOH solution with a volume of 400 mL contains 2 moles of KOH. What is the molarity of the solution? </li></ul><ul><li>M = 2 mole KOH = 5 M </li></ul><ul><li> 0.4 L </li></ul>
  6. 6. <ul><li>Calculate the molarity of a solution prepared by mixing 1.5 g of NaCl in 500.0 mL of water.   </li></ul><ul><li>First calculate the moles of solute: </li></ul><ul><li>1.5 g NaCl ( 1 mole NaCl ) = 0.0257 moles of NaCl </li></ul><ul><li>       58.45 g NaCl </li></ul><ul><li>Next convert mL to L: 0.500 L of solution </li></ul><ul><li>Last, plug the appropriate values into the correct variables in the equation: </li></ul><ul><li>M = n / V = 0.0257 moles / 0.500 L = 0.051 mol/L </li></ul>
  7. 7. Molarity Calculation <ul><li>NaOH is used to open stopped sinks, to treat </li></ul><ul><li>cellulose in the making of nylon, and to </li></ul><ul><li>remove potato peels commercially. </li></ul><ul><li>If 4.0 g NaOH are used to make 500. mL of NaOH solution, what is the molarity (M) of the solution? </li></ul>
  8. 8. <ul><li>1) 4.0 g NaOH x 1 mole NaOH = 0.10 mole NaOH </li></ul><ul><li>40.0 g NaOH </li></ul><ul><li>2) 500. mL x 1 L _ = 0.500 L </li></ul><ul><li> 1000 mL </li></ul><ul><li>3. 0.10 mole NaOH = 0.20 mole NaOH </li></ul><ul><li>0.500 L 1 L </li></ul><ul><li> = 0.20 M NaOH </li></ul>
  9. 9. <ul><li>A glucose solution with a volume of 2.0 L contains 72 g glucose (C 6 H 12 O 6 ). </li></ul><ul><li>What is the molarity of the glucose solution? </li></ul>
  10. 10. <ul><li>A glucose solution with a volume of 2.0 L contains 72 g glucose (C 6 H 12 O 6 ). </li></ul><ul><li>What is the molarity of the glucose solution? </li></ul><ul><li>72 g x 1 mole x 1 = 0.20 M </li></ul><ul><li> 180. g 2.0 L </li></ul>
  11. 11. Molarity Conversion Factors <ul><li>A solution is a 3.0 M NaOH. . Write the molarity in the form of conversion factors. </li></ul><ul><li> 3.0 moles NaOH and 1 L NaOH soln </li></ul><ul><li> 1 L NaOH soln 3.0 moles NaOH </li></ul>
  12. 12. <ul><li>Stomach acid is a 0.10 M HCl solution. How many moles of HCl are in 1500 mL of stomach acid solution? </li></ul>
  13. 13. Stomach acid is a 0.10 M HCl solution. How many moles of HCl are in 1500 mL of stomach acid solution? 1500 mL x 1 L = 1.5 L 1000 mL 1.5 L x 0.10 mole HCl = 0.15 mole HCl 1 L
  14. 14. <ul><li>How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution? </li></ul>
  15. 15. Molarity Calculation <ul><li>NaOH is used to open stopped sinks, to treat </li></ul><ul><li>cellulose in the making of nylon, and to </li></ul><ul><li>remove potato peels commercially. </li></ul><ul><li>If 4.0 g NaOH are used to make 500. mL of NaOH solution, what is the molarity (M) of the solution? </li></ul>
  16. 16. <ul><li>1) 4.0 g NaOH x 1 mole NaOH = 0.10 mole NaOH </li></ul><ul><li>40.0 g NaOH </li></ul><ul><li>2) 500. mL x 1 L _ = 0.500 L </li></ul><ul><li> 1000 mL </li></ul><ul><li>3. 0.10 mole NaOH = 0.20 mole NaOH </li></ul><ul><li>0.500 L 1 L </li></ul><ul><li> = 0.20 M NaOH </li></ul>
  17. 17. <ul><li>A glucose solution with a volume of 2.0 L contains 72 g glucose (C 6 H 12 O 6 ). </li></ul><ul><li>What is the molarity of the glucose solution? </li></ul>
  18. 18. <ul><li>A glucose solution with a volume of 2.0 L contains 72 g glucose (C 6 H 12 O 6 ). </li></ul><ul><li>What is the molarity of the glucose solution? </li></ul><ul><li>72 g x 1 mole x 1 = 0.20 M </li></ul><ul><li> 180. g 2.0 L </li></ul>
  19. 19. <ul><li>Stomach acid is a 0.10 M HCl solution. How many moles of HCl are in 1500 mL of stomach acid solution? </li></ul>
  20. 20. Stomach acid is a 0.10 M HCl solution. How many moles of HCl are in 1500 mL of stomach acid solution? 1500 mL x 1 L = 1.5 L 1000 mL 1.5 L x 0.10 mole HCl = 0.15 mole HCl 1 L
  21. 21. <ul><li>How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution? </li></ul>
  22. 22. <ul><li>How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution? </li></ul><ul><li>400. mL x 1 L = 0.400 L </li></ul><ul><li> 1000 mL </li></ul><ul><li>0.400 L x 3.0 mole NaOH x 40.0 g NaOH 1 L 1 mole NaOH </li></ul><ul><li>(molar mass) </li></ul><ul><li>= 48 g NaOH </li></ul>

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