---
title: "A copper-recycling sample contains both copper metal, \\(\\text{Cu(s)}\\), and copper(II) oxide, \\(\\text{CuO(s)}\\). A student adds dilute \\(\\text{HNO}_3\\text{(aq)}\\) to the sample. Both substances dissolve, but gas is produced only while \\(\\text{Cu(s)}\\) remains. The student writes the following net ionic equations for the dissolution processes.  \\[ \\text{CuO(s)}+2\\text{H}^{+}\\text{(aq)}\\rightarrow\\text{Cu}^{2+}\\text{(aq)}+\\text{H}_2\\text{O(l)} \\]  \\[ 3\\text{Cu(s)}+2\\text{NO}_3^{-}\\text{(aq)}+8\\text{H}^{+}\\text{(aq)}\\rightarrow3\\text{Cu}^{2+}\\text{(aq)}+2\\text{NO(g)}+4\\text{H}_2\\text{O(l)} \\]  Which statement correctly distinguishes the two dissolution pathways and justifies the distinction?"
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url: "https://nerd-notes.com/ubq/120092/"
date_modified: "2026-08-21T08:41:31+00:00"
---

# A copper-recycling sample contains both copper metal, \(\text{Cu(s)}\), and copper(II) oxide, \(\text{CuO(s)}\). A student adds dilute \(\text{HNO}_3\text{(aq)}\) to the sample. Both substances dissolve, but gas is produced only while \(\text{Cu(s)}\) remains. The student writes the following net ionic equations for the dissolution processes.

\[
\text{CuO(s)}+2\text{H}^{+}\text{(aq)}\rightarrow\text{Cu}^{2+}\text{(aq)}+\text{H}_2\text{O(l)}
\]

\[
3\text{Cu(s)}+2\text{NO}_3^{-}\text{(aq)}+8\text{H}^{+}\text{(aq)}\rightarrow3\text{Cu}^{2+}\text{(aq)}+2\text{NO(g)}+4\text{H}_2\text{O(l)}
\]

Which statement correctly distinguishes the two dissolution pathways and justifies the distinction?

A copper-recycling sample contains both copper metal, \(\text{Cu(s)}\), and copper(II) oxide, \(\text{CuO(s)}\). A student adds dilute \(\text{HNO}_3\text{(aq)}\) to the sample. Both substances dissolve, but gas is produced only while \(\text{Cu(s)}\) remains. The student writes the following net ionic equations for the dissolution processes.

\[
\text{CuO(s)}+2\text{H}^{+}\text{(aq)}\rightarrow\text{Cu}^{2+}\text{(aq)}+\text{H}_2\text{O(l)}
\]

\[
3\text{Cu(s)}+2\text{NO}_3^{-}\text{(aq)}+8\text{H}^{+}\text{(aq)}\rightarrow3\text{Cu}^{2+}\text{(aq)}+2\text{NO(g)}+4\text{H}_2\text{O(l)}
\]

Which statement correctly distinguishes the two dissolution pathways and justifies the distinction?

- **A.** Both dissolution processes are Brønsted–Lowry acid-base reactions because each consumes \(\text{H}^{+}\text{(aq)}\) and forms \(\text{H}_2\text{O(l)}\).
- **B.** Both dissolution processes are oxidation–reduction reactions because each produces \(\text{Cu}^{2+}\text{(aq)}\) from a reactant that contains \(\text{Cu}\).
- **C.** The dissolution of \(\text{CuO(s)}\) is a Brønsted–Lowry acid-base reaction, whereas the dissolution of \(\text{Cu(s)}\) is an oxidation–reduction reaction, because no oxidation numbers change in the first process and \(\text{Cu(s)}\) is the oxidizing agent in the second process as its oxidation number increases from \(0\) to \(+2\).
- **D.** The dissolution of \(\text{CuO(s)}\) is a Brønsted–Lowry acid-base reaction, whereas the dissolution of \(\text{Cu(s)}\) is an oxidation–reduction reaction, because oxide accepts protons without oxidation-number changes, while \(\text{Cu}\) changes from \(0\) to \(+2\) and \(\text{N}\) in \(\text{NO}_3^{-}\) changes from \(+5\) to \(+2\).

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/120092/*