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Preparation of different solutions using different methods for concentration expression

Preparation of different solutions using different methods for concentration expression . Purpose :. To learn how to use some common accurate measures. 2) To learn how to calculate the amount of solute required for solution preparation.

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Preparation of different solutions using different methods for concentration expression

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  1. Preparation of different solutions using different methods for concentration expression

  2. Purpose : • To learn how to use some • common accurate measures. • 2) To learn how to calculate the amount of solute required for solution preparation. • 3)To learn how to prepare solution from solid or from stock • solution.

  3. Introduction : Different ways to express the concentration of solutions. Molar solution Gram percent (g%w/v) X gram of solute dissolved in 100 ml of solvent A molar solution is the solution that contains gram molecular weight of the substance in a liter of solution.

  4. One of the most common ways to prepare a solution is to dilute a concentrated solution that has already been prepared.OR Preparation of a solution from solid by calculation of appropriate quantity then dissolve in appropriate volume of solution. ??????

  5. C is the concentration V is the volume Moles of solute before dilution = Moles of solute after dilutionC1V1 = C2 V2C1&C2 have the same units V1&V2 have the same units

  6. e.g. Choose the correct answer. • Calculate the amount of water needed to dilute 150 mL of a solution having a concentration of 10M to 3M • 500 mL b) 650 mL c) 350 mL d) 450 mL C1V1 = C2 V2 150 x 10 = 3 x V2 V2=500 mL Since we must add 350 mL of water to reach to a final solution = 500 mL

  7. Preparation of a solution from solid

  8. I-preparation of 0.1 M NaCl : • Note: You are supplied with NaCl powder (M.Wt = 58.5) . • 1)Calculate amount of NaCl required • to prepare 100 ml of 0.1 M NaCl. • 2)Weigh accurately the calculated • amount • 3)Transfer into 100-ml volumetric flask. • 4)Add 25 ml of water, shake well to dissolve and • then complete the volume to mark with water and mix well 0.1M NaCl = 0.1 M.Wt /L

  9. II-preparation of 0.5 g% w/v NaCl 0.5 g • 1)Calculate amount of NaCl required • to prepare 100 ml of 0.5g %w/v NaCl • 2)Weigh accurately the calculated • amount • 3)Transfer into 100-ml volumetric flask. • 4)Add 25 ml of water, shake well to dissolve and • then complete the volume to mark with water and mix well

  10. Preparation of a solution from stock solution

  11. III – preparation of 1 g %w/v NaCl from stock solution of NaCl ( 1 g / ml ) • a)Calculate the volume • of stock NaCl required. • b)Transfer accurately ( Burrette) the calculated volume • to 100 mL volumetric flask. • c ) Add water , shake well and then complete • to th to the mark with water and mix well

  12. Important Problems : I ) Calculate the mL that should be taken from a stock of NaOH (0.01g/mL), to prepare 100mL of 0.01M NaOH. II) Calculate the mL that should be taken from a stock of HCl (0.02 g/ml), prepare 100ml of 0.2M HCl. III ) Calculate the mL that should be taken from a stock of sodium acetate (0.2g/ mL), prepare 100mL of 0.1M sodium acetate. (mol wt of sod. Acetate= 82)

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