User:Moira M. Esson/Notebook/CHEM-581/2012/08/31: Difference between revisions
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# Pour into a 500 mL volumetric flask and fill with H<sub>2</sub>O. | # Pour into a 500 mL volumetric flask and fill with H<sub>2</sub>O. | ||
# Dilute the solution by pouring the following volumes into separate 50 mL volumetric flasks and then filling with H<sub>2</sub>O. | # Dilute the solution by pouring the following volumes into separate 50 mL volumetric flasks and then filling with H<sub>2</sub>O. | ||
#* | '''Stock Solution Calculations''' | ||
# | |||
# | * Stock Solution Preparation for PVOH (MW 22000) | ||
{| {{table}} | |||
| align="center" style="background:#f0f0f0;"|'''Initial Mass [g]''' | |||
| align="center" style="background:#f0f0f0;"|'''Additional Mass [g]''' | |||
| align="center" style="background:#f0f0f0;"|'''Total Mass [g]''' | |||
| align="center" style="background:#f0f0f0;"|'''Stock Volume [mL]''' | |||
| align="center" style="background:#f0f0f0;"|'''Concentration ['''M''']''' | |||
| align="center" style="background:#f0f0f0;"|'''Weight percent [%]''' | |||
|- | |||
| 2.0256||4.9902||7.0158||500||6.38E-4||1.40||| | |||
|} | |||
*Serial Dilution of PVOH Stock Solution | |||
| align="center" style="background:#f0f0f0;"|'''Dilution''' | |||
| align="center" style="background:#f0f0f0;"|''''''M<sub>1</sub'''[mol/L]''' | |||
| align="center" style="background:#f0f0f0;"|''''''V<sub>1</sub''' [mL]''' | |||
| align="center" style="background:#f0f0f0;"|''''''M<sub></sub'''[mol/L]''' | |||
| align="center" style="background:#f0f0f0;"|''''''V<sub>1</sub''' [mL]''' | |||
|- | |||
| 1||6.38E-04||6.25||7.98E-05||50|| | |||
| 2||6.38E-04||12.5||1.59E-04||50|| | |||
| 3||6.38E-04||25 ||3.19E-04||50|| | |||
| 4||6.38E-04||35.5||4.78E-04||50|| | |||
|} | |||
==Viscosity of PVOH (MW 22000) Stock Solution== | ==Viscosity of PVOH (MW 22000) Stock Solution== | ||
'''General Procedure''': | '''General Procedure''': |
Revision as of 20:16, 6 September 2012
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Objectives
PVOH plus acid films
Preparation of PVOH Stock Solutions
Stock Solution Calculations
|
Dilution | 'M1</sub'[mol/L] | 'V1</sub' [mL] | 'M</sub'[mol/L] | 'V1</sub' [mL] | ||||||||||||||||||
1 | 6.38E-04 | 6.25 | 7.98E-05 | 50 | 2 | 6.38E-04 | 12.5 | 1.59E-04 | 50 | 3 | 6.38E-04 | 25 | 3.19E-04 | 50 | 4 | 6.38E-04 | 35.5 | 4.78E-04 | 50 |
Viscosity of PVOH (MW 22000) Stock Solution
General Procedure:
- Using an ASTM kinematic viscometer, time the rate at which H2O flows from the top most line to the bottom most line. Run at least three trials
- Note:The actual amount of solution in the viscometer does not matter, but the viscometer can hold no more than 10mL. Approximately 10mL should be used
- Measure the temperature of the surroundings. Record the temperature
- Wash the viscometer with the solution that needs to be tested. Wash by drawing the solution into the viscometer with a pipette pump past the top of the lower bulb and then allowing the solution to drain
- Wash the viscometer at least two times then discard the solution
- Pour approximately 10mL of the solution into the viscometer
- Draw the solution up past the lower bulb of the viscometer using a pipette pump
- Remove the pipette pump and let the solution drain from the viscometer. Once the bottom of the meniscus passes the first mark on the viscometer, start a stopwatch
- Stop the stop watch once the bottom of the meniscus passes the lower mark on the viscometer
- Repeat steps 6 through 8 at least two more times to obtain an average time in seconds for the solution to move between the two marks.
- Note: Solutions should be run through the viscometer with increasing concentration(i.e. The lowest concentrated stock solution should be used first)
Viscosity Calculations
- Viscosity of pure H2O at 26°C
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 at 26°C
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 at 26°C
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 at 26°C
Trial [ ] | Time [s] |
1 | 273.99 |
2 | 276.73 |
3 | 278.63 |
- Average time = 276.45 s
Preparation
- Prepared 500mL stock solution of PVOH (MW 130,000)in H2O
Observations
- PVOH (MW 130,000) film(prepared 08/29/12) when dried was very rigid and curled slightly
- Preparation of 500mL stock solution of PVOH (MW 130,000)in H2O required more time(~2-2.5 hrs). Complete dissolution of the polymer required extra time and more vigorous stirring
- When dissolving the PVOH (MW 130,000) a large gel-like sphere formed in the center of the solution
Notes
- An additional 2-3mL H2O was added to each solution to aid in the complete dissolution of the PVOH
- Heat was reduced halfway through dissolving the PVOH because the solutions began to boil too rapidly
- When pouring the ~0.5g PVOH (MW 22000) with HCl there was a small loss of sample when pouring the solution into a Teflon dish
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