Chemistry Extended Essay Exemplar: pH and Methylene Blue Adsorption… | RevisionDojo

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IB Chemistry SL Extended Essay Example

How does pH (3, 5, 7, 9, 11) affect the equilibrium adsorption capacity of 10 ppm methylene blue onto 0.5g of granular activated carbon, and which kinetic model, pseudo-first-order or pseudo-second-order, best describes this process?SL

Official IB Result

IB Grade: B

Criteria A: Focus and Method

5/6

Criteria StrandsPro

A.1Topic communication and explanation

Excellent

A.2Research question formulation and focus

Good

A.3Research methodology

Moderate

Criteria Feedback

The student communicates a clear and chemically relevant investigation with a focused environmental context.
The student's research question is explicit, operational, and easy to follow.
The student's method shows thoughtful experimental planning with repeated trials and relevant measurements.

The kinetic part of the question is narrower than the wording suggests, because it is only tested at one pH.
Some methodological controls are not fully described, especially pH confirmation, uncertainty handling, and treatment of anomalies.
A few choices rely on conditions that are not fully justified by the specific carbon material used.

Criteria B: Knowledge and Understanding

4/6

Criteria StrandsPro

B.1Application of source material

Moderate

B.2Subject knowledge

Moderate

B.3Use of terminology and concepts

Moderate

Criteria Feedback

The student applies source material to the actual investigation in a mostly relevant and coherent way.
The student demonstrates solid knowledge of adsorption, surface chemistry, calibration, and kinetic modelling.
The student uses subject-specific terminology with good consistency and generally accurate definitions.

Some mechanistic explanations are not fully precise, especially the interaction language used for adsorption on charged sites.
The kinetic models are sometimes interpreted too categorically, without enough caution about what a good fit can and cannot prove.
A few outside sources are transferred from systems that are not fully comparable to the student's activated carbon sample.

Criteria C: Critical Thinking

8/12

Criteria StrandsPro

C.1Research quality

Moderate

C.2Analysis depth

Poor

C.3Discussion and evaluation

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: Presentation

2/4

Criteria StrandsPro

D.1Structure appropriateness

Excellent

D.2Layout considerations

Excellent

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...

Official IB Result

IB Grade: B

Criteria A: Focus and Method

5/6

Criteria StrandsPro

A.1Topic communication and explanation

Excellent

A.2Research question formulation and focus

Good

A.3Research methodology

Moderate

Criteria Feedback

The student communicates a clear and chemically relevant investigation with a focused environmental context.
The student's research question is explicit, operational, and easy to follow.
The student's method shows thoughtful experimental planning with repeated trials and relevant measurements.

The kinetic part of the question is narrower than the wording suggests, because it is only tested at one pH.
Some methodological controls are not fully described, especially pH confirmation, uncertainty handling, and treatment of anomalies.
A few choices rely on conditions that are not fully justified by the specific carbon material used.

Criteria B: Knowledge and Understanding

4/6

Criteria StrandsPro

B.1Application of source material

Moderate

B.2Subject knowledge

Moderate

B.3Use of terminology and concepts

Moderate

Criteria Feedback

The student applies source material to the actual investigation in a mostly relevant and coherent way.
The student demonstrates solid knowledge of adsorption, surface chemistry, calibration, and kinetic modelling.
The student uses subject-specific terminology with good consistency and generally accurate definitions.

Some mechanistic explanations are not fully precise, especially the interaction language used for adsorption on charged sites.
The kinetic models are sometimes interpreted too categorically, without enough caution about what a good fit can and cannot prove.
A few outside sources are transferred from systems that are not fully comparable to the student's activated carbon sample.

Criteria C: Critical Thinking

8/12

Criteria StrandsPro

C.1Research quality

Moderate

C.2Analysis depth

Poor

C.3Discussion and evaluation

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: Presentation

2/4

Criteria StrandsPro

D.1Structure appropriateness

Excellent

D.2Layout considerations

Excellent

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.