User:Monika Gasiorek/Notebook/CHEM-571 2014F/2014/09/02: Difference between revisions
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|style="background-color: #EEE"|[[Image:owwnotebook_icon.png|128px]]<span style="font-size:22px;"> Project name</span> | |style="background-color: #EEE"|[[Image:owwnotebook_icon.png|128px]]<span style="font-size:22px;"> Project name</span> | ||
|style="background-color: #F2F2F2" align="center"| | |style="background-color: #F2F2F2" align="center"|[[File:Report.png|frameless|link={{#sub:{{FULLPAGENAME}}|0|-11}}]][[{{#sub:{{FULLPAGENAME}}|0|-11}}|Main project page]]<br />{{#if:{{#lnpreventry:{{FULLPAGENAME}}}}|[[File:Resultset_previous.png|frameless|link={{#lnpreventry:{{FULLPAGENAME}}}}]][[{{#lnpreventry:{{FULLPAGENAME}}}}{{!}}Previous entry]] }}{{#if:{{#lnnextentry:{{FULLPAGENAME}}}}|[[{{#lnnextentry:{{FULLPAGENAME}}}}{{!}}Next entry]][[File:Resultset_next.png|frameless|link={{#lnnextentry:{{FULLPAGENAME}}}}]]}} | ||
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==September 2, 2014== | |||
==Titrant Stock Solution Preparation and Standardization== | ==Titrant Stock Solution Preparation and Standardization== | ||
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*approximately 0.500 g of KHPhth in approximately 15-30 mL of H<sub>2</sub>O was titrated with the stock titrant in the presence of phenolphthalein indicator for a total of 4 trials | *approximately 0.500 g of KHPhth in approximately 15-30 mL of H<sub>2</sub>O was titrated with the stock titrant in the presence of phenolphthalein indicator for a total of 4 trials | ||
*the molarity of the NaOH titrant was calculated for the 2 trials that demonstrated reproducible results | *the molarity of the NaOH titrant was calculated for the 2 trials that demonstrated reproducible results | ||
'''NOTE''':The first trial did not result in a color change. The second trial required approx. 25 mL of NaOH for a color change to be observed. The error here could be | '''NOTE''':The first trial did not result in a color change. The second trial required approx. 25 mL of NaOH for a color change to be observed. The error here could possibly be due to the failure to completely dissolve all of the solid NaOH crystals in 500 mL of water. The stock bottle was shaken properly before the 3rd and 4th trials, resulting in reproducible results. | ||
The calculated average for the NaOH titrant stock solution was 0.1575 M. | |||
The data from the titrant standardization is included below. | |||
==<font color=#0f1028></font>== | |||
{|style="width:700px" | |||
|<u>'''Trial'''</u> | |||
|<u>'''KHPhth (g)'''</u> | |||
|<u>'''NaOH added (mL)'''</u> | |||
|<u>'''Molarity (mol/L)'''</u> | |||
|- | |||
|1 | |||
|0.49870 | |||
|-X | |||
|-X | |||
|- | |||
|2 | |||
|0.50399 | |||
|25.00 | |||
|0.09871 | |||
|- | |||
|3 | |||
|0.50230 | |||
|15.80 | |||
|0.1557 | |||
|- | |||
|4 | |||
|0.50264 | |||
|15.45 | |||
|0.1593 | |||
|} | |||
==Hydrophobic Amino Acid Titration: Valine== | |||
A solution of valine was titrated with the 0.1575 M NaOH titrant in order to produce a characteristic titration curve for valine. | |||
*a calculation was done to determine the amount of solid valine that would be required for complete titration with 20 mL of 0.1575 M NaOH | |||
*a 0.3678 g sample of valine was dissolved in 10 mL of 21 mM HCl, as well as 10 mL of H<sub>2</sub>0 [Trial 1] | |||
*a 0.3689 g sample of valine was dissolved in 10 mL of 21 mM HCl, as well as 10 mL of H<sub>2</sub>0 [Trial 2] | |||
A pH probe was calibrated and used to track the change in pH as additional amounts of 0.1575 M NaOH were added over time. | |||
*two trials were done, with respective data presented below | |||
**trial 1 followed a basic schematic of 5 mL increments, followed by a more thorough 2nd trial guided by the data demonstrated in trial 1 | |||
*a pH curve was constructed from the data points in each trial | |||
==<font color=#0f1028></font>== | |||
{|style="width:700px" | |||
|<u>'''Trial'''</u> | |||
|<u>'''NaOH added (mL)'''</u> | |||
|<u>'''pH'''</u> | |||
|- | |||
|1 | |||
|0.00 | |||
|3.317 | |||
|- | |||
|1 | |||
|5.00 | |||
|9.106 | |||
|- | |||
|1 | |||
|10.00 | |||
|9.631 | |||
|- | |||
|1 | |||
|15.00 | |||
|10.087 | |||
|- | |||
|1 | |||
|20.00 | |||
|10.945 | |||
|} | |||
==<font color=#0f1028></font>== | |||
{|style="width:700px" | |||
|<u>'''Trial'''</u> | |||
|<u>'''NaOH added (mL)'''</u> | |||
|<u>'''pH'''</u> | |||
|- | |||
|2 | |||
|0.00 | |||
|3.346 | |||
|- | |||
|2 | |||
|1.00 | |||
|8.263 | |||
|- | |||
|2 | |||
|2.00 | |||
|8.263 | |||
|- | |||
|2 | |||
|3.00 | |||
|8.675 | |||
|- | |||
|2 | |||
|4.00 | |||
|8.949 | |||
|- | |||
|2 | |||
|5.00 | |||
|9.115 | |||
|- | |||
|2 | |||
|6.00 | |||
|9.254 | |||
|- | |||
|2 | |||
|7.00 | |||
|9.370 | |||
|- | |||
|2 | |||
|8.00 | |||
|9.473 | |||
|- | |||
|2 | |||
|9.00 | |||
|9.568 | |||
|- | |||
|2 | |||
|10.00 | |||
|9.659 | |||
|- | |||
|2 | |||
|12.50 | |||
|9.901 | |||
|- | |||
|2 | |||
|15.00 | |||
|10.139 | |||
|- | |||
|2 | |||
|17.50 | |||
|10.459 | |||
|- | |||
|2 | |||
|20.00 | |||
|11.071 | |||
|} | |||
[[Image:Valine_Titration_T1.png|500px]] | |||
[[Image:Valine_Titration_T2.png|500px]] | |||
<!-- ##### DO NOT edit below this line unless you know what you are doing. ##### --> | <!-- ##### DO NOT edit below this line unless you know what you are doing. ##### --> |
Latest revision as of 00:13, 27 September 2017
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September 2, 2014Titrant Stock Solution Preparation and Standardization500 mL of approximately 0.150 M NaOH solution was prepared from 2.99978 g of solid NaOH and 500 mL of H2O.
The titrant was standardized in order to determine the actual concentration.
NOTE:The first trial did not result in a color change. The second trial required approx. 25 mL of NaOH for a color change to be observed. The error here could possibly be due to the failure to completely dissolve all of the solid NaOH crystals in 500 mL of water. The stock bottle was shaken properly before the 3rd and 4th trials, resulting in reproducible results. The calculated average for the NaOH titrant stock solution was 0.1575 M. The data from the titrant standardization is included below.
Hydrophobic Amino Acid Titration: ValineA solution of valine was titrated with the 0.1575 M NaOH titrant in order to produce a characteristic titration curve for valine.
A pH probe was calibrated and used to track the change in pH as additional amounts of 0.1575 M NaOH were added over time.
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