Description
What ideas can help translate the challenge of global inequality into a manifesto for change?
Answer this question by a) defining an issue area and ‘case’ (e.g. climate change in Chile, or global pandemics and international trade negotiations), b) explaining the causes of inequalities in this area drawing on ideas covered in the first half of the course, c) naming your goal (e.g. free universal education, ecological debt payments), d) proposing policy and other social changes needed to achieve your proposed goal, and e) considering and replying to possible limitations and criticisms of your proposal.
You don’t need to reinvent the wheel. You can draw on existing proposals for addressing inequalities in public policy. In fact, you’re encouraged to do this.
The research report will apply sociological analysis to contemporary issue of global inequality and development, related to themes discussed in weeks 7-12 (gender, health, education, mining, climate change etc). You will have scope to choose your issue area and precise topic (e.g. gender equality and education policy in Indonesia).
Assessment criteria
1) Sophisticated explanation of the causes of inequality;
2) Well-defined issue and proposal for change;
3) Focused answer in response to the essay question;
4) Appropriate and critical use of evidence;
5) Clear written expression;
6) Attention to detail in citation and references using Harvard style.
Choosing an indicator
CHEM 253 (Fall 2021)
Choosing the correct indicator for an acid-base titration is very important. Acid-base indicators are an
acid or base which is different colors at different pHs. Each indicator changes colors at its pKas and
has a known transition range. The difference between the observed end point (color change) and the
true equivalence point is called the indicator error.
In this experiment you will standardize NaOH with oxalic acid dihydrate using several different
indicators. You will compare the accuracy of different indicators in locating the end point.
Standardization
1. Transfer approximately the mass of oxalic acid dihydrate that you calculated from the titration
lab into a 50 mL beaker. Record this mass to three decimal places.
2. Transfer this to a 125 mL Erlenmeyer flask using between 15 and 20 mL of DI water as a rinse.
Make sure all of the acid has dissolved before continuing.
3. Add to this acid solution three drops of your assigned indicator and swirl to mix. The solution
should be colorless.
4. Set up a buret with the NaOH solution from the lab bench. Be sure to condition the buret
properly before using. Verify that there are no bubbles in the tip and record the initial volume
reading (to two decimal places).
5. Deliver the titrant NaOH into the flask containing the acid, swirling continuously. Stop when the
solution changes color for the end point. Record the final volume reading (to two decimal
places).
6. Repeat this titration with all assigned indicators 2x each.
Using the actual mass of the oxalic acid dihydrate (H2C2O4 ·2H2O) and the volume of titrant added,
calculate the actual molarity of the NaOH solution for each titration completed and note which
indicator was used.
Post lab:
• Download the group dataset and use a Grubbs test to decide if any results should be discard
from each set of indicator data.
• For each indicator, calculate the average and standard deviation, and the Confidence interval
for each indicator. Does each C.I contain the known molarity of the NaOH? Does each
indicator give similar results?
• From the data, select two indicators and conduct a paired t-test to determine whether the two
indicators give different results at the 95% confidence interval. Treat each indicator as a
different sample and follow Harris’ example on page 77 in the text to conduct the t-test using
formulas in Excel. Check your work with the built in paired t-test analysis package in Excel.
indicator
pH range
Molarites
Average
Standerd Deviation
indicator
phenolphthalein
8 10
methyl orange
3.1 4.4
congo red
3.50
0.1490
0.1510
0.146
0.159
0.1170
0.1430
0.1538
0.1511
0.1100
0.1070
0.0861
0.1520
0.1460
0.1340
0.025667714
0.214
0.220
0.1931
0.1955
0.1685
0.1385
0.1268
0.0500
0.0958
0.2187
0.2876
0.2320
0.2870
0.185157143
0.028020639
bromochresol green
4-5.6
bromocresol purple
5.2-6.8
thymolththalein
9.4 – 10.6
methyl red
4.4 – 6.2
bromothymol blue
6 – 7.6
0.103
0.108
0.1015
0.1094
0.10650
0.10850
0.1480
0.1440
0.10520
0.10600
0.1682
0.1723
0.1999
0.1538
0.131
0.128
0.1328
0.1295
0.1072
0.1085
0.15367
0.1501
0.1123
0.09658
0.10400
0.10900
0.06508
0.09875
0.10000
0.1079
0.1137
0.1132
0.1123
0.1139
0.1182
0.1162
0.10530
0.10760
0.10600
0.10900
0.1111
0.1100
xylenol orange methyl violet
6.8 0 – 1.6
0.1028
0.1087
300.6
299
0.108
0.107
0.1505
0.1525
0.1109
60.19
58.13
15.8
42.7
3.71
42.5
42.1
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