# User:Melissa Novy/Notebook/CHEM-581/2012/08/31

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## Objectives

• Make PVOH films plus concentrated acid in H2O.
• Make 0.16 mM stock solution of PVOH in H2O, then dilute by 0.75, 0.5, 0.25, and 0.625.

## PVOH Plus Acid Films

• 0.5 g PVOH (MW 22,000) and 2 drops of 12 M HCl in 3 mL H2O
• Actual mass PVOH = 0.5163 g
• 1 g PVOH (MW 22,000) and 1 drop of 12 M H2SO4 in 6 mL H2O
• Actual mass PVOH = 1.0204 g
• 1 g PVOH (MW 22,000) and 1 drop of 12 M H3PO4 in 6 mL H2O
• Actual mass PVOH = 1.0040 g

## PVOH Stock Solutions

1. Dissolve 7 g PVOH (MW 22,000) in 200 mL H2O, stirring and heating to about 90°C.
2. Let the solution cool to room temperature.
3. Pour into a 500 mL volumetric flask and fill with H2O.
4. Dilute the solution by pouring the following volumes into separate 50 mL volumetric flasks and then filling with H2O.
• Concentration of original stock solution = 15.95 mM
• Use 37.5 mL of 15.95 mM solution to dilute to 11.96 mM
• Use 25 mL of 15.95 mM solution to dilute to 7.98 mM
• Use 1.25 mL of 15.95 mM solution to dilute to 3.99 mM
• Use 6.25 mL of 15.95 mM solution to dilute to 1.99 mM

## Viscosity of PVOH (MW 22,000) Stock Solutions

• Viscosity of pure H2O
 Trial [ ] Time [s] 1 238.79 2 242.62 3 241.63
• Average time = 241.01 s

• Viscosity of 1.99 mM PVOH in H2O
 Trial [ ] Time [s] 1 279.37 2 281.97 3 283.12
• Average time = 281.49 s

• Viscosity of 3.99 mM PVOH in H2O
 Trial [ ] Time [s] 1 246.42 2 250.31 3 251.86
• Average time = 249.53 s

• Viscosity of 7.98 mM PVOH in H2O
 Trial [ ] Time [s] 1 273.99 2 276.73 3 278.63
• Average time = 276.45 s