Experiment Details - Experimentium

Experiment of Buffer Details

VIDEO LINKS:

Experimental Protocol

Chemical Table

(Representation) Prepare your chemical table including the materials you will use in the experiment.  Here is a general template that you may use.
<table width="671">
<tbody>
<tr>
<td width="78">Chemical Name</td>
<td width="78">Chemical Formula</td>
<td width="68">Molar Mass (g/mol)</td>
<td width="77">Hazards</td>
<td width="314">Reference</td>
<td width="56">PPE</td>
</tr>
<tr>
<td width="78">Sodium Chloride</td>
<td width="78">NaCl</td>
<td width="68">58.5</td>
<td width="77">Skin irritation</td>
<td width="314"><a href="https://fscimage.fishersci.com/msds/21105.htm">https://fscimage.fishersci.com/msds/21105.htm</a></td>
<td width="56"> </td>
</tr>
<tr>
<td width="78"></td>
<td width="78"></td>
<td width="68"></td>
<td width="77"></td>
<td width="314"></td>
<td width="56"></td>
</tr>
<tr>
<td width="78"></td>
<td width="78"></td>
<td width="68"></td>
<td width="77"></td>
<td width="314"></td>
<td width="56"></td>
</tr>
<tr>
<td width="78"> </td>
<td width="78"> </td>
<td width="68"> </td>
<td width="77"> </td>
<td width="314"> </td>
<td width="56"> </td>
</tr>
<tr>
<td width="78"> </td>
<td width="78"> </td>
<td width="68"> </td>
<td width="77"> </td>
<td width="314"> </td>
<td width="56"> </td>
</tr>
<tr>
<td width="78"> </td>
<td width="78"> </td>
<td width="68"> </td>
<td width="77"> </td>
<td width="314"> </td>
<td width="56"> </td>
</tr>
<tr>
<td width="78"> </td>
<td width="78"> </td>
<td width="68"> </td>
<td width="77"> </td>
<td width="314"> </td>
<td width="56"> </td>
</tr>
</tbody>
</table>

Equipment Table

Data Collection

Data Processing

<ol>
 	<li>(Representation) Write the balanced equation for the dissociation of HOOCCH3 in water.</li>
 	<li>(Representation) Write the balanced equation for the dissociation of NaOOCCH3 in water.</li>
 	<li>(Analysis) Using Le Chatelier’s principle, show how the addition of NaOOCCH3 in a HOOCCH3 solution affects the equilibrium.</li>
 	<li>(Manipulation) Calculate the pKa for the conjugate acid in your buffer solution.</li>
 	<li>(Manipulation) Show how the Henderson-Hasselbalch equation was used to get the ratio of conjugate base to conjugate acid in your buffer solution at your specified pH.</li>
 	<li>(Manipulation) Calculate the moles of acid in your buffer.</li>
 	<li>(Manipulation) Calculate the moles of conjugate base in your buffer.</li>
 	<li>(Manipulation) Calculate the initial concentration of acetate ion, acetic acid, sodium ion and hydronium* ion in the acetic acid-sodium acetate buffer with a pH=5.05.</li>
 	<li>(Manipulation) Calculate the hydronium* ion and chloride ion concentrations in the HCl solution with pH=5.05.</li>
 	<li>(Manipulation) Calculate the hydronium* ion and chloride ion concentrations in the HCl solution with pH=5.05 after addition of 1 mL of 1M HCl.</li>
 	<li>(Manipulation) Calculate the hydronium* ion and chloride ion concentrations in the HCl solution with pH=5.05 after addition of 1 mL of 1M NaOH.</li>
 	<li>(Manipulation) Calculate the initial concentration of acetate ion, acetic acid, sodium ion and hydronium* ion in the acetic acid-sodium acetate buffer with a pH=5.05, after addition of 1 mL of 1M HCl.</li>
 	<li>(Manipulation) Calculate the initial concentration of acetate ion, acetic acid, sodium ion and hydronium ion in the acetic acid-sodium acetate buffer with a pH=5.05, after addition of 1 mL of 1M NaOH.</li>
 	<li>(Manipulation) A buffer loses its buffering capacity when either the strong base or strong acid within is consumed. Calculate the volume of 1.0 M NaOH that would cause this buffer to lose its buffering capacity.</li>
 	<li>(Manipulation) A buffer loses its buffering capacity when either the strong base or strong acid within is consumed. Calculate the volume of 1.0 M HCl that would cause this buffer to lose its buffering capacity.</li>
 	<li>(Interpretation) Identify the most effective pH range of your benzoic acid buffer.</li>
 	<li>(Manipulation) Based on your final pH reading, calculate the concentration of sodium benzoate in the buffer solution.</li>
 	<li>(Assumptions and Analysis) Fill in the following table using the observations and data from your experiments.</li>
</ol>
<table width="659">
<tbody>
<tr>
<td width="248">Assumptions made</td>
<td width="195">Testing the assumption</td>
<td width="216">If assumptions are wrong ...</td>
</tr>
<tr>
<td width="248">Destroying a buffer requires the same amount of acid as base.</td>
<td width="195">Add equal moles of acid and base to equal volumes of buffer solution</td>
<td width="216">Different amounts of acid and base will be used to dramatically change the pH.</td>
</tr>
<tr>
<td width="248"></td>
<td width="195"></td>
<td width="216"></td>
</tr>
<tr>
<td width="248"></td>
<td width="195"></td>
<td width="216"></td>
</tr>
</tbody>
</table>
&nbsp;

*The 2005 IUPAC rules changed the name of hydronium to oxonium, but most resources still use hydronium when referring to H3O+

Discussion

Write a minimum one-page (12 font, single spaced) discussion on the experiment conducted this week. Address at least one question in each category as fully as possible integrating the collected data, providing explanations for the observed trends, and evaluating whether your original assumptions about the experiment were validated by the results. The assignment will be graded on completeness, clarity of the explanations and the meaningful integration of the collected and calculated data. Correct grammar and appropriate format for the chemical formulae and chemical reactions is expected. You may use the outline included at the end of this document on how to build your essay to address each category.
<ol>
 	<li>(Existing knowledge, research, and views) Define buffers and describe one method for making a buffer.</li>
 	<li>(Interpretation) Describe the method for determining the hydronium ion concentration for a buffer solution.</li>
 	<li>(Analysis) Using your calculations and your observations, provide a supported argument for the difference in behavior of a buffer compared to a strong acid solution, if both have the same pH.</li>
 	<li>(Analysis) Using your calculations and your observations, provide a supported argument for the difference in behavior of a buffer compared to a weak acid solution, if both have the same pH.</li>
 	<li>(Analysis) Describe how buffers work to resist changes in pH when reacted with acids and bases.</li>
 	<li>(Existing knowledge, research, and views) Identify the buffer range of the acetic acid/sodium acetate buffer solutions, if the pKa of acetic acid is 4.75.</li>
 	<li>(Existing knowledge, research, and views) At what ratio of weak acid to conjugate base is a buffer equally effective against both acid and base attacks?</li>
 	<li>(Experiment design) Describe the process of making another buffer system of a specific pH. (Ex. Acetic acid and sodium acetate buffers at a pH of 4.75.)</li>
 	<li>(Analysis) Provide a supported argument for using pKa rather than Ka when describing buffers.</li>
 	<li>(Experiment design) Propose a method for making a buffer if you only have a weak acid and a strong base available.</li>
 	<li>(Analysis) Evaluate whether adding a weak acid with a weak base will result in a buffer solution. Provide a supported argument for your choice.</li>
 	<li>(Analysis) If all our additions were performed using 1.0 M solutions. Describe how changing to 0.1 M solutions would affect the buffer range.</li>
 	<li>(Analysis) If all our additions were performed using 1.0 M solutions. Describe how changing to 0.1 M solutions would affect the buffering capacity.</li>
 	<li>(Analysis) Acetic acid is a monoprotic weak acid. Describe at least one change you would expect if acetic acid was replaced by a diprotic acid like carbonic acid and provide a supporting argument for your choice.</li>
 	<li>(Existing knowledge, research, and views) Besides blood, list 3 other buffer systems common in nature.</li>
 	<li>(Analysis) Ammonia is a weak base. Predict the buffer range of the buffer prepared using ammonia and its conjugate acid.</li>
 	<li>(Analysis) Contact solution, lemonade mixes, shampoos are all buffered products. Provide a supported argument for the benefit of using buffered system in these products.</li>
</ol>