---
title: "A student conducts an experiment to determine the composition of a bronze alloy containing only \\(\\text{Cu}\\) and \\(\\text{Sn}\\). A \\(2.46 \\text{ g}\\) sample of the alloy is dissolved completely in excess concentrated \\(\\text{HNO}_3\\text{(aq)}\\). During the reaction, all of the tin is oxidized to insoluble hydrated tin(IV) oxide, while the copper dissolves to form \\(\\text{Cu}^{2+}\\text{(aq)}\\). The precipitate is collected by filtration, washed, and heated to constant mass in a crucible to yield anhydrous \\(\\text{SnO}_2\\text{(s)}\\). The student records the laboratory data in the table below.  | Measurement | Value | | :— | :— | | Mass of bronze alloy sample | \\(2.46 \\text{ g}\\) | | Mass of empty crucible and cover | \\(18.50 \\text{ g}\\) | | Mass of crucible, cover, and \\(\\text{SnO}_2\\text{(s)}\\) after heating | \\(20.01 \\text{ g}\\) | | Molar mass of \\(\\text{Cu}\\) | \\(63.5 \\text{ g/mol}\\) | | Molar mass of \\(\\text{Sn}\\) | \\(119 \\text{ g/mol}\\) | | Molar mass of \\(\\text{SnO}_2\\) | \\(151 \\text{ g/mol}\\) |  Based on the data in the table, what is the mole fraction of \\(\\text{Cu}\\) in the bronze alloy sample?"
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url: "https://nerd-notes.com/ubq/120195/"
date_modified: "2026-08-21T16:02:59+00:00"
---

# A student conducts an experiment to determine the composition of a bronze alloy containing only \(\text{Cu}\) and \(\text{Sn}\). A \(2.46 \text{ g}\) sample of the alloy is dissolved completely in excess concentrated \(\text{HNO}_3\text{(aq)}\). During the reaction, all of the tin is oxidized to insoluble hydrated tin(IV) oxide, while the copper dissolves to form \(\text{Cu}^{2+}\text{(aq)}\). The precipitate is collected by filtration, washed, and heated to constant mass in a crucible to yield anhydrous \(\text{SnO}_2\text{(s)}\). The student records the laboratory data in the table below.

| Measurement | Value |
| :— | :— |
| Mass of bronze alloy sample | \(2.46 \text{ g}\) |
| Mass of empty crucible and cover | \(18.50 \text{ g}\) |
| Mass of crucible, cover, and \(\text{SnO}_2\text{(s)}\) after heating | \(20.01 \text{ g}\) |
| Molar mass of \(\text{Cu}\) | \(63.5 \text{ g/mol}\) |
| Molar mass of \(\text{Sn}\) | \(119 \text{ g/mol}\) |
| Molar mass of \(\text{SnO}_2\) | \(151 \text{ g/mol}\) |

Based on the data in the table, what is the mole fraction of \(\text{Cu}\) in the bronze alloy sample?

A student conducts an experiment to determine the composition of a bronze alloy containing only \(\text{Cu}\) and \(\text{Sn}\). A \(2.46 \text{ g}\) sample of the alloy is dissolved completely in excess concentrated \(\text{HNO}_3\text{(aq)}\). During the reaction, all of the tin is oxidized to insoluble hydrated tin(IV) oxide, while the copper dissolves to form \(\text{Cu}^{2+}\text{(aq)}\). The precipitate is collected by filtration, washed, and heated to constant mass in a crucible to yield anhydrous \(\text{SnO}_2\text{(s)}\). The student records the laboratory data in the table below.

| Measurement | Value |
| :--- | :--- |
| Mass of bronze alloy sample | \(2.46 \text{ g}\) |
| Mass of empty crucible and cover | \(18.50 \text{ g}\) |
| Mass of crucible, cover, and \(\text{SnO}_2\text{(s)}\) after heating | \(20.01 \text{ g}\) |
| Molar mass of \(\text{Cu}\) | \(63.5 \text{ g/mol}\) |
| Molar mass of \(\text{Sn}\) | \(119 \text{ g/mol}\) |
| Molar mass of \(\text{SnO}_2\) | \(151 \text{ g/mol}\) |

Based on the data in the table, what is the mole fraction of \(\text{Cu}\) in the bronze alloy sample?

- **A.** \(0.33\)
- **B.** \(0.67\)
- **C.** \(0.75\)
- **D.** \(0.80\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/120195/*