Buffers Lab Discussion, chemistry homework help

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  1. In the discussion you should make a conclusion and then explain how your experimental results and observations support your conclusion. The points below should help you identify the information you have available from this experiment to support your conclusion. Submit completed lab report by due date. you should be able to make a claim about which buffer system is most effective and support this claim with both theoretical calculations and experimental evidence. Be sure to include the following:
    1. a. Introduction. Find one instance of the importance of buffers to life or to the environment and write a SHORT paragraph about the chemistry, referencing all sources.
    2. b. Purpose. Based upon the introduction in your lab manual, what are you trying to find with your experiment?
    3. c. Claim. Based upon the purpose of your experiment, what claim can you make using your experimental evidence?
    4. d. Table(s) of your results. Include expected, experimental, and % error as appropriate.
    5. e. Discussion of your results.
      1. Which buffer had the highest capacity for added acid? Is this consistent with your expected results? Use a graph and a table of your experimental results to support your conclusion.
      2. Which buffer had the highest capacity for added base? Is this consistent with your expected results? Use a graph and a table of your experimental results to support your conclusion.
    6. f. Uncertainty and Error in measurements.
      1. Identify possible sources of uncertainty and error in your measurements
      2. Comment on the relevance for each possible source of error. Based on the magnitude and direction of the error source and evidence from your laboratory notebook, determine if each source of error is relevant for your results.
    7. g. Supporting references.
    I'll send the data base when the work is assigned

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Experiment 6: Buffers Question: What is a buffer solution? Goals 1. Students understand how a buffer works. 2. Students learn how to prepare an effective buffer solution. 3. Students discover the concept of buffer capacity. Objectives 1. Students gain additional experience measuring pH. 2. Students prepare buffer solutions and test the effect of adding acid and base. Introduction Buffers are solutions that resist a change in pH when small quantities of acids or bases are added. In this experiment, you will examine potential buffer systems and determine their effectiveness. Students should be able to make a claim about which buffer system is most effective and support this claim with both theoretical calculations and experimental evidence. Equipment 1. pH probe 2. Universal indicator solution with card 3. Burets 4. 20 mL, 25 mL and 50 mL Volumetric pipets Reagents 1. 0.0500 M Acetic acid solution 2. 0.100 M Hydrochloric acid solution 3. 0.100 M Sodium hydroxide solution 4. Sodium acetate (solid) Resources 1. CRC Handbook of Chemistry and Physics - You may use any edition 2. NIOSH Pocket Guide to Chemical Hazards (NPG) - http://www.cdc.gov/niosh/npg/ 3. SIRI MSDS Database - http://siri.org/msds/index.php 4. Chemistry Laboratory Information Profiles, CD-ROM or http://www.acs.org/content/acs/en/about/governance/committ ees/chemicalsafety/safety practices/clips-list.html 5. Comprehensive Guide to Chemical Resistant Best Gloves - http://www.chemrest.com/ Safety and Pre-Lab Before starting the experiment, complete the Safety and Pre-Lab template. Procedure Use the pH meters. Be sure to review the directions for their use before beginning To calibrate the pH meter: a. Turn on b. Place in pH 7 buffer, wait until the reading stabilizes, and press “cal”. Wait until meter reads “En” c. Rinse with DI water into a waste beaker and blot dry with a Kimwipe d. Place in pH 4 buffer, and repeat steps b and c e. Place in pH 10 buffer, and repeat steps b and c Part 1: Preparation of Solutions Each student in your group will make a different solution and determine if it is an effective buffer. You will make 50 mL of the buffer. Pipet out two 20 mL portions. You will titrate one portion with acid and one portion with base. Solution #1: 50.0 mL of 0.0500 M acetic acid and 0.205 grams of sodium acetate Solution #2: 25.0 mL of 0.0500 M acetic acid, 25.0 mL of deionized water, and 0.205 grams of sodium acetate Solution #3: 50.0 mL of 0.0500 M acetic acid and 0.102 grams of sodium acetate Solution #4: 50.0 mL of 0.0500 M acetic acid Solution #5: 50 mL of deionized water and 0.205 grams of sodium acetate Solution #6: 50 mL of deionized water
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Explanation & Answer

Kindly see attached file with the corresponding report

Introduction
Buffers are used in our daily life whenever it is important to maintain the pH of a given solution. In this
regard, a sample industrial application of a buffer solution would be the alcoholic fermentation of beer.
In this sense, an acetic acid / sodium acetate buffer is used as reaction medium to enable the yeast to
survive in its optimal pH range, such that it can ferment sugar into ethanol during the alcoholic
fermentation process, essential in the beer production (Torija et al., 2003). On the other hand, buffers
are essential for life since we would die if the pH of our blood was lower than 6.8 or higher than 7.8 as
all the enzymatic systems in our body would stop working outside this pH range. The pH of the blood is
maintained constant through the carbonic acid / bicarbonate buffering system (Casiday & Frey, n.d.).

Purpose
The purpose of this experiment is to examine how buffers work by maintaining the pH constant despite
the addition of different amounts of acid (HCl) or base (NaOH).

Claim
If buffers are able of keeping the pH of the solution constant, then the pH of the solution will not vary
unless a very big amount of a strong acid (such as HCl) or a strong base (such as NaOH) are added to the
solution.

Results
Table 1. Buffer solutions prepared
Solution
1
2
3
4
5
6

Concentration of acetic acid, M
0.050
0.025
0.050
0.050
0.000
0.000

Concentration of sodium acetate, M
0.0619
0.0514
0.0259
0.0000
0.0507
0.0000

Table 1 presents the concentrations of both acetic acid and sodium acetate in the prepared buffer
solutions. These solutions were prepared by adequately diluting different volumes of a 0.05 M acetic
acid solution and solving specific amounts of sodium acetate. The final volume of all the solutions was of
50.0 mL.
The significant figures in this table have been established by considering the significant figures of the
methodology used in the preparation of the diffe...


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