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A student made a standard solution by transferring0.0400g of NaCLinto 50ml volum

ID: 75437 • Letter: A

Question

A student made a standard solution by transferring0.0400g of NaCLinto 50ml volumetric flask, dissolving the salt and diluting themark. She then withdrew 5ml aliquot with a volumetric pipet andtransferred to a 50ml volumetric flask. The solution was diluted tothe mark. Calculate the concentration of the sodium in parts permillion. Assume that 1ml=1g.
Steps by step procedure to acquiring the answer to theabove would be truly appreciated.
Answer: 31.72ppm
Steps by step procedure to acquiring the answer to theabove would be truly appreciated.
Answer: 31.72ppm

Explanation / Answer

Find mols of NaCl so you can find mols of Na+ 0.0400g (1mol/58.48g) = 0.00068 mols of Na + (1:1dissociation) Find the conc of the original. C = 0.00068 mols of Na + / 0.050 L = 0.0137 M Find the mols of aliquot. n = 0.0137 M * 0.005 L = 6.83E-5 mols Find the desired concentration. C = 6.83E-5 mols / 0.050L = 0.00136789.... M Convert to ppm.... 31.72ppm