1) Describe how to prepare 5.00 liters of a 5.00% (w/w)NaCl solution, which has
ID: 691171 • Letter: 1
Question
1) Describe how to prepare 5.00 liters of a 5.00% (w/w)NaCl solution, which has a density of 1.06 g/mL, from pure solidsodium chloride. 2) Describe how to prepare 2.00 liters of 0.20 M NaOH solutionfrom 50% (w/w) NaOH solution that has a density of 1.53 g/mL, anddoing all measurements by volume (not mass). 1) Describe how to prepare 5.00 liters of a 5.00% (w/w)NaCl solution, which has a density of 1.06 g/mL, from pure solidsodium chloride. 2) Describe how to prepare 2.00 liters of 0.20 M NaOH solutionfrom 50% (w/w) NaOH solution that has a density of 1.53 g/mL, anddoing all measurements by volume (not mass). 2) Describe how to prepare 2.00 liters of 0.20 M NaOH solutionfrom 50% (w/w) NaOH solution that has a density of 1.53 g/mL, anddoing all measurements by volume (not mass).Explanation / Answer
(1) 5% (w/w) solution means 5 g of NaCl dissolved in 100 g ofsolvent Density , d = mass / Volume So Volume of the solvent , V = massof solvent / density =100 g / 1.06 g / mL = 94.34 mL So 5g of NaCl dissolved in 94.34 mL of the solvent X g of NaCl dissolved in 5000mL of thesolvent X = ( 5*5000 ) / 94.34 = 264.9989 g of NaCl So 264.9989 g of NaCl solid is taken and is dissolved in 5000mL of the solvent. (2) Describe how to prepare 2.00 liters of 0.20 MNaOH solution from 50% (w/w) NaOH solution that has a density of1.53 g/mL, and doing all measurements by volume (not mass). 50% (w/w) solution means 50 g of NaOH dissolved in 100 g ofsolvent Density , d = mass / Volume So Volume of the solvent , V = massof solvent / density =100 g / 1.53 g / mL = 65.36 mL So 50g of NaOH dissolved in 65.36 mL of the solvent Therefore Molarity of the solution , M = ( mass / Molar mass) / Volume of the solution =( 50 / 40 ) / 0.06536 L = 19.1248 M From law of dilution MV = M'V' M= Molarity of stock = 19.1248 M M' = Molarity of dilute solution = 0.2 M V = Volume of stock = ? V' = Volume of dilute solution = 2L Plug the values we get V = M'V' / M = 0.02091 L = 20.9 mL So 20.9 mL of the stock solution is taken in a 2L Volumetricflask & made upto the mark with the diluent. Density , d = mass / Volume So Volume of the solvent , V = massof solvent / density =100 g / 1.53 g / mL = 65.36 mL So 50g of NaOH dissolved in 65.36 mL of the solvent Therefore Molarity of the solution , M = ( mass / Molar mass) / Volume of the solution =( 50 / 40 ) / 0.06536 L = 19.1248 M From law of dilution MV = M'V' M= Molarity of stock = 19.1248 M M' = Molarity of dilute solution = 0.2 M V = Volume of stock = ? V' = Volume of dilute solution = 2L Plug the values we get V = M'V' / M = 0.02091 L = 20.9 mL So 20.9 mL of the stock solution is taken in a 2L Volumetricflask & made upto the mark with the diluent.Related Questions
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