Chemistry Extended Essay Exemplar: To what extent does changing the… | RevisionDojo

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IB Chemistry SL Extended Essay Example

To what extent does changing the initial concentration of thiocyanate ions influence the observed pseudo-first-order rate constant for the formation of the iron(III) thiocyanate complex as determined by UV-Visible spectrophotometry?SL

Official IB Result

IB Grade: B

Criteria A: Focus and Method

4/6

Criteria Strands

A.1Topic communication and explanation

Excellent

A.2Research question formulation and focus

Good

A.3Research methodology

Moderate

Criteria Feedback

You communicate a specific and appropriate chemical investigation with a clear spectrophotometric purpose.
Your research question is focused, measurable, and directly linked to the variable you manipulate.
You include a substantial method with repeated trials, controlled variables, and practical awareness of timing and mixing issues.

Your kinetic model needs clearer justification so the relationship between the rate law and the variable you vary is unambiguous.
The method is missing some important experimental details such as wavelength, blank/reference procedure, and pH or acid conditions.
The timing of measurements is too slow for the reaction timescale, which weakens the reliability of the kinetic design.

Criteria B: Knowledge and Understanding

4/6

Criteria Strands

B.1Application of source material

Moderate

B.2Subject knowledge

Moderate

B.3Use of terminology and concepts

Moderate

Criteria Feedback

You show sound understanding of the chemistry behind the coloured iron(III)–thiocyanate system and why UV-Vis monitoring is appropriate.
You use a range of relevant chemical terminology and concepts with mostly accurate control.
You apply source material in ways that support the discussion of spectroscopy, coordination chemistry, and kinetic behaviour.

Your kinetic explanation is not fully coherent, especially where the treatment of the observed rate constant changes across the essay.
Some chemical claims need tighter support and clearer distinction between what is generally plausible and what is established for this specific system.
A few important concepts, such as Beer–Lambert assumptions and ionic-strength effects, are mentioned but not always explained with enough precision.

Criteria C: Critical Thinking

8/12

Criteria Strands

C.1Research quality

Poor

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 Strands

D.1Structure appropriateness

Good

D.2Layout considerations

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.

Loading scores...

Official IB Result

IB Grade: B

Criteria A: Focus and Method

4/6

Criteria Strands

A.1Topic communication and explanation

Excellent

A.2Research question formulation and focus

Good

A.3Research methodology

Moderate

Criteria Feedback

You communicate a specific and appropriate chemical investigation with a clear spectrophotometric purpose.
Your research question is focused, measurable, and directly linked to the variable you manipulate.
You include a substantial method with repeated trials, controlled variables, and practical awareness of timing and mixing issues.

Your kinetic model needs clearer justification so the relationship between the rate law and the variable you vary is unambiguous.
The method is missing some important experimental details such as wavelength, blank/reference procedure, and pH or acid conditions.
The timing of measurements is too slow for the reaction timescale, which weakens the reliability of the kinetic design.

Criteria B: Knowledge and Understanding

4/6

Criteria Strands

B.1Application of source material

Moderate

B.2Subject knowledge

Moderate

B.3Use of terminology and concepts

Moderate

Criteria Feedback

You show sound understanding of the chemistry behind the coloured iron(III)–thiocyanate system and why UV-Vis monitoring is appropriate.
You use a range of relevant chemical terminology and concepts with mostly accurate control.
You apply source material in ways that support the discussion of spectroscopy, coordination chemistry, and kinetic behaviour.

Your kinetic explanation is not fully coherent, especially where the treatment of the observed rate constant changes across the essay.
Some chemical claims need tighter support and clearer distinction between what is generally plausible and what is established for this specific system.
A few important concepts, such as Beer–Lambert assumptions and ionic-strength effects, are mentioned but not always explained with enough precision.

Criteria C: Critical Thinking

8/12

Criteria Strands

C.1Research quality

Poor

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 Strands

D.1Structure appropriateness

Good

D.2Layout considerations

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.