Chemistry Extended Essay Exemplar: Ionic Radii and Iron Nail Corrosion | RevisionDojo

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IB Chemistry SL Extended Essay Example

How does the magnitude of ionic radii of cations, specifically Sodium (Na+), Magnesium (Mg2+), Calcium (Ca2+), and Potassium (K+), in chloride salts, affect the corrosion rate on an iron nail as measured through immersion tests and spectrophotometry over 6 days?SL

Official IB Result

IB Grade: B

Criteria A: Focus and Method

5/6

Criteria Strands

A.1Topic communication and explanation

Excellent

A.2Research question formulation and focus

Excellent

A.3Research methodology

Excellent

Criteria Feedback

Research question is stated clearly and unambiguously, with precise scope and variables defined.
Dual-method design is thoroughly described with clear procedural summaries and appropriate controls.
Background and rationale are coherent and maintain focus on the effect of ionic radius throughout.

Minor gaps in methodology justification (e.g. pH control not addressed, limited justification for chloride concentration).
Small omissions prevent full methodological perfection, dropping the strand from a 6 to a 5.

Criteria B: Knowledge and Understanding

5/6

Criteria Strands

B.1Application of source material

Excellent

B.2Subject knowledge

Excellent

B.3Use of terminology and concepts

Excellent

Criteria Feedback

Consistent and accurate use of specialist terminology and chemical notation throughout.
Clear and coherent subject knowledge linking macroscopic observations to microscopic corrosion processes.
Broad range of relevant peer-reviewed and industrial sources integrated to justify theory and methodology.

A few figures and tables lack explicit attribution, indicating sporadic citation lapses.
Occasional oversimplifications (e.g. treating mass gain strictly as corrosion rate) prevent full mastery.

Criteria C: Critical Thinking

7/12

Criteria Strands

C.1Research quality

Good

C.2Analysis depth

Moderate

C.3Discussion and evaluation

Moderate

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: Presentation

3/4

Criteria Strands

D.1Structure appropriateness

Good

D.2Layout considerations

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...

Official IB Result

IB Grade: B

Criteria A: Focus and Method

5/6

Criteria Strands

A.1Topic communication and explanation

Excellent

A.2Research question formulation and focus

Excellent

A.3Research methodology

Excellent

Criteria Feedback

Research question is stated clearly and unambiguously, with precise scope and variables defined.
Dual-method design is thoroughly described with clear procedural summaries and appropriate controls.
Background and rationale are coherent and maintain focus on the effect of ionic radius throughout.

Minor gaps in methodology justification (e.g. pH control not addressed, limited justification for chloride concentration).
Small omissions prevent full methodological perfection, dropping the strand from a 6 to a 5.

Criteria B: Knowledge and Understanding

5/6

Criteria Strands

B.1Application of source material

Excellent

B.2Subject knowledge

Excellent

B.3Use of terminology and concepts

Excellent

Criteria Feedback

Consistent and accurate use of specialist terminology and chemical notation throughout.
Clear and coherent subject knowledge linking macroscopic observations to microscopic corrosion processes.
Broad range of relevant peer-reviewed and industrial sources integrated to justify theory and methodology.

A few figures and tables lack explicit attribution, indicating sporadic citation lapses.
Occasional oversimplifications (e.g. treating mass gain strictly as corrosion rate) prevent full mastery.

Criteria C: Critical Thinking

7/12

Criteria Strands

C.1Research quality

Good

C.2Analysis depth

Moderate

C.3Discussion and evaluation

Moderate

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

3/4

Criteria Strands

D.1Structure appropriateness

Good

D.2Layout considerations

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.