An aqueous solution of copper sulfate is a clear blue colour - VCE - SSCE Chemistry - Question 9 - 2002 - Paper 1
Question 9
An aqueous solution of copper sulfate is a clear blue colour. The concentration of this solution is to be measured using UV-visible spectroscopy.
An aqueous copper ... show full transcript
Worked Solution & Example Answer:An aqueous solution of copper sulfate is a clear blue colour - VCE - SSCE Chemistry - Question 9 - 2002 - Paper 1
Step 1
absorb mainly red light and therefore allow blue light to pass through the solution.
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Answer
Copper sulfate has a blue color because it absorbs light in the red region of the spectrum. As a result, when light passes through a solution of copper sulfate, the red wavelengths are absorbed while the blue wavelengths are transmitted. Therefore, the correct answer is B.
Step 2
absorb mainly blue light and therefore allow red light to pass through the solution.
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Answer
This statement is incorrect because if copper sulfate absorbs mainly blue light, it would not appear blue; instead, it would transmit blue light and absorb red light.
Step 3
absorb mainly blue light and therefore allow blue light to pass through the solution.
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Answer
This statement contradicts the understanding of how color absorption works. If copper sulfate absorbed blue light, the solution would appear colorless, not blue.
Step 4
absorb mainly red light and therefore allow blue light to pass through the solution.
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Answer
This choice is similar to the correct one but labels the absorbed light incorrectly. Copper sulfate does absorb red light, which is why blue light is transmitted.
