User:Melissa Novy/Notebook/CHEM-581/2012/09/21

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Objectives

  • Dilute 20 ppm SO4-2 stock solutions made on 2012/09/19 to be used for atomic absorption calibration.
  • Analyze DSC data taken on 2012/09/14.
  • Prepare fixant solutions for PVOH-glutaraldehyde crosslinking next week. Please refer to Moira Esson's entry for the protocol and safety notes.

Dilutions

  • Calculations
  MW Na2SO4: 142.04 g/mol
  MW Na+: 22.99 g/mol
  Mass Na+: 0.00150 g Na2SO4 × (1 mol Na2SO4/142.04 g Na2SO4) × (2 mol Na+/1 mol Na2SO4) × (22.99 g Na+/1 mol Na+) = 4.856 × 10-4 g Na+
  Actual concentration of Na+ in 2020 ppm SO4-2 solution:
  (4.856 × 10-4 g Na+)/0.5 L × 106 = 971 ppm
  (971 ppm)(0.00495 L) = (M2)(0.5 L)
  M2 = 9.61 ppm Na+


  MW CuSO4·5H2O: 249.69 g/mol
  MW Cu+2: 63.55 g/mol 
  0.00252 g CuSO4·5H2O × (1 mol CuSO4·5H2O/249.68 g CuSO4·5H2O) × (1 mol Cu+2/1 mol CuSO4·5H2O) × (63.55 g Cu+2/1 mol CuSO4·5H2O) = 6.41 × 10-4 g Cu+2
  Actual concentration of Cu+2 in 2020 ppm SO4-2 solution:
  (6.41 × 10-4 g Cu+2)/0.5 L × 106 = 1283 ppm Cu+2
  (1283 ppm)(5.16 mL) = (M2)(0.5 L)
  M2 = 13.2 ppm Cu+2

DSC Data





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