Chemistry IA Exemplar: To investigate the effect of varying pH on… | RevisionDojo

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IB Chemistry HL Internal Assessment Example

To investigate the effect of varying pH on the rate of ethanol oxidation to ethanoic acid by acidified potassium dichromate (VI), measured through absorbance change at 430 nm using a colorimeter, while controlling temperature, reagent volumes, concentrations, temperature, wavelength, and time period.HL

Overall Score

21/24

Criteria A: Research Design

4/6

Criteria Strands

A.1Research question context

Excellent

A.2Methodological considerations

Moderate

A.3Methodology description

Moderate

Criteria Feedback

Your research question is focused, chemistry-specific, and clearly identifies the variables being investigated.
You provide relevant background on the dichromate/chromium(III) system and why absorbance at 430 nm is a sensible measurement approach.
Your method includes several practical details such as repeats, temperature control, and set reaction volumes.

The design does not fully keep pH as the only changing factor because the buffer substitution also changes concentration and solution composition.
Some chemical explanations are oversimplified or inaccurate, especially around the role of protons in the reaction.
There are ambiguities in how the timing and pH preparation were handled, which makes complete replication difficult.

Criteria B: Data Analysis

5/6

Criteria Strands

B.1Communication of data recording and processing

Moderate

B.2Consideration of uncertainties

Moderate

B.3Data processing quality

Poor

Criteria Feedback

You present your raw and processed results in a readable structure with tables that make comparisons across pH values easy to follow.
You use a sensible preliminary processing approach by calculating absorbance change per unit time and summarising repeated trials.
You consider random variation by including uncertainty estimates based on the spread of repeated rates.

The timing information is inconsistent across the method, tables, and discussion, which makes the reported rates harder to trust.
The analysis does not properly address the large change in starting absorbance across pH values, even though this suggests a dilution effect.
Important uncertainties from instruments and pH measurement are not included, so the uncertainty treatment is incomplete.

Criteria C: Conclusion

6/6

Criteria Strands

C.1Conclusion relevance and support

Moderate

C.2Scientific context comparison

Poor

Criteria Feedback

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Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Criteria D: Evaluation

6/6

Criteria Strands

D.1Methodological weaknesses

Good

D.2Suggested improvements

Good

Criteria Feedback

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Loading scores...

Overall Score

21/24

Criteria A: Research Design

4/6

Criteria Strands

A.1Research question context

Excellent

A.2Methodological considerations

Moderate

A.3Methodology description

Moderate

Criteria Feedback

Your research question is focused, chemistry-specific, and clearly identifies the variables being investigated.
You provide relevant background on the dichromate/chromium(III) system and why absorbance at 430 nm is a sensible measurement approach.
Your method includes several practical details such as repeats, temperature control, and set reaction volumes.

The design does not fully keep pH as the only changing factor because the buffer substitution also changes concentration and solution composition.
Some chemical explanations are oversimplified or inaccurate, especially around the role of protons in the reaction.
There are ambiguities in how the timing and pH preparation were handled, which makes complete replication difficult.

Criteria B: Data Analysis

5/6

Criteria Strands

B.1Communication of data recording and processing

Moderate

B.2Consideration of uncertainties

Moderate

B.3Data processing quality

Poor

Criteria Feedback

You present your raw and processed results in a readable structure with tables that make comparisons across pH values easy to follow.
You use a sensible preliminary processing approach by calculating absorbance change per unit time and summarising repeated trials.
You consider random variation by including uncertainty estimates based on the spread of repeated rates.

The timing information is inconsistent across the method, tables, and discussion, which makes the reported rates harder to trust.
The analysis does not properly address the large change in starting absorbance across pH values, even though this suggests a dilution effect.
Important uncertainties from instruments and pH measurement are not included, so the uncertainty treatment is incomplete.

Criteria C: Conclusion

6/6

Criteria Strands

C.1Conclusion relevance and support

Moderate

C.2Scientific context comparison

Poor

Criteria Feedback

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Criteria D: Evaluation

6/6

Criteria Strands

D.1Methodological weaknesses

Good

D.2Suggested improvements

Good

Criteria Feedback

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.