Question

The student dissolves the entire impure sample of CuSO4(s) in enough distilled water to make 100.ML of solution. Then the student measures the absorbance of the solution and observes that it is 0.30 . Determine the concentration of CuSO4(aq) in the solution.

Answer 1

Answer:

Here's what I get  

Explanation:

I assume you prepared a calibration curve — a plot of the absorbance vs the concentrations of known solutions.

It probably looked like the one below.

You drew the best straight line that went as close as possible to all the points without necessarily going through any of them.

Now you have a CuSO₄ solution with an absorbance of 0.30.

You start at 0.30 on the vertical axis and draw a line horizontally until it hits your best-fit line.

Then you draw a vertical line to the horizontal axis and read the corresponding concentration.

It hits the axis at 0.15 mol·L⁻¹.

You would say that the concentration of CuSO₄ is 0.15 mol·L⁻¹.