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Edexcel A-Level Chemistry A2 B 3 1 Translating Between Data Forms Questions

Practise Edexcel IAL Chemistry translating between data forms by reading graphs, calibration curves and best-fit lines to obtain chemical quantities.

Syllabus
Pearson Edexcel International Advanced Subsidiary/Advanced Level
Course
Chemistry XCH11/YCH11
Level
A2

Exam points

  • Read values from straight-line or calibration graphs, showing construction lines when marks require them.
  • Convert graphical readings into concentrations, ppm values or diluted-sample results using the given scale factors.
  • Use best-fit lines to predict chemical quantities such as ionic radius, percentage ethanol or C=C count.

Edexcel A-Level Chemistry A2 B 3 1 Translating Between Data Forms Questions question 1

[Maximum number: 2]

This question is about coloured transition metal complex ions.

Colorimetry was used to determine the concentration of a solution of copper（II）sulfate．
Six solutions of copper（II）sulfate of known concentration were prepared and their absorbance at a wavelength of 635 nm measured．The results are shown．

Table for Question Edexcel A-Level Chemistry A2 B 3 1 Translating Between Data Forms Questions question 1 — Edexcel A-Level Chemistry A2

50.0 cm350.0 \mathrm{~cm}^{3} of a solution of copper(II) sulfate of unknown concentration was pipetted into a 250.0 cm3250.0 \mathrm{~cm}^{3} volumetric flask and the volume made up to the

mark with deionised water.
The absorbance at a wavelength of 635 nm for this diluted copper(II) sulfate solution was 0.72.

Determine the concentration of the original copper(II) sulfate solution. You must show your working on the graph.

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