---
title: "A student determines the concentration of \\(\\text{Cu}^{2+}\\text{(aq)}\\) in a solution using spectrophotometry. The student transfers a \\(10.0\\text{ mL}\\) sample of the original solution into a volumetric flask and adds distilled water to make \\(100.0\\text{ mL}\\) of diluted solution. The absorbance of the diluted solution, measured at the wavelength of maximum absorbance in a cuvette with a path length of \\(1.00\\text{ cm}\\), is \\(0.240\\). If the molar absorptivity (\\(\\epsilon\\)) of the absorbing species at this wavelength is \\(80.0\\text{ M}^{-1}\\text{cm}^{-1}\\), what was the concentration of \\(\\text{Cu}^{2+}\\text{(aq)}\\) in the original solution before dilution?"
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url: "https://nerd-notes.com/ubq/121381/"
date_modified: "2026-08-23T05:02:00+00:00"
---

# A student determines the concentration of \(\text{Cu}^{2+}\text{(aq)}\) in a solution using spectrophotometry. The student transfers a \(10.0\text{ mL}\) sample of the original solution into a volumetric flask and adds distilled water to make \(100.0\text{ mL}\) of diluted solution. The absorbance of the diluted solution, measured at the wavelength of maximum absorbance in a cuvette with a path length of \(1.00\text{ cm}\), is \(0.240\). If the molar absorptivity (\(\epsilon\)) of the absorbing species at this wavelength is \(80.0\text{ M}^{-1}\text{cm}^{-1}\), what was the concentration of \(\text{Cu}^{2+}\text{(aq)}\) in the original solution before dilution?

A student determines the concentration of \(\text{Cu}^{2+}\text{(aq)}\) in a solution using spectrophotometry. The student transfers a \(10.0\text{ mL}\) sample of the original solution into a volumetric flask and adds distilled water to make \(100.0\text{ mL}\) of diluted solution. The absorbance of the diluted solution, measured at the wavelength of maximum absorbance in a cuvette with a path length of \(1.00\text{ cm}\), is \(0.240\). If the molar absorptivity (\(\epsilon\)) of the absorbing species at this wavelength is \(80.0\text{ M}^{-1}\text{cm}^{-1}\), what was the concentration of \(\text{Cu}^{2+}\text{(aq)}\) in the original solution before dilution?

- **A.** \(3.00 \times 10^{-4}\text{ M}\)
- **B.** \(3.00 \times 10^{-3}\text{ M}\)
- **C.** \(1.50 \times 10^{-2}\text{ M}\)
- **D.** \(3.00 \times 10^{-2}\text{ M}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121381/*