---
title: "A student analyzes a solid salt blend recovered from a thermal-storage system. The blend contains only \\(\\text{NaCl}\\), \\(\\text{KCl}\\), and \\(\\text{KNO}_3\\). Separate representative portions of the blend, each with a mass of \\(3.085\\text{ g}\\), are analyzed as shown below.  | Analysis | Procedure | Measured result | |—|—|—| | Precipitation | The portion is dissolved, excess \\(\\text{AgNO}_3\\text{(aq)}\\) is added, and the precipitate is dried. | \\(4.305\\text{ g}\\) of \\(\\text{AgCl(s)}\\) | | Thermal decomposition | The portion is heated until only \\(\\text{KNO}_3\\) decomposes and the mass becomes constant. | Final mass of \\(2.925\\text{ g}\\) |  The relevant processes are  \\[ \\text{Ag}^{+}\\text{(aq)}+\\text{Cl}^{-}\\text{(aq)}\\rightarrow\\text{AgCl(s)} \\]  and  \\[ 2\\,\\text{KNO}_3\\text{(s)}\\rightarrow 2\\,\\text{KNO}_2\\text{(s)}+\\text{O}_2\\text{(g)}. \\]  The relevant molar masses are \\(M_{\\text{NaCl}}=58.5\\text{ g mol}^{-1}\\), \\(M_{\\text{KCl}}=74.5\\text{ g mol}^{-1}\\), \\(M_{\\text{KNO}_3}=101.0\\text{ g mol}^{-1}\\), \\(M_{\\text{AgCl}}=143.5\\text{ g mol}^{-1}\\), and \\(M_{\\text{O}_2}=32.0\\text{ g mol}^{-1}\\). Which of the following gives the mole-percent composition of the original blend in the order \\(\\text{NaCl}\\), \\(\\text{KCl}\\), and \\(\\text{KNO}_3\\)?"
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url: "https://nerd-notes.com/ubq/120115/"
date_modified: "2026-08-21T08:41:45+00:00"
---

# A student analyzes a solid salt blend recovered from a thermal-storage system. The blend contains only \(\text{NaCl}\), \(\text{KCl}\), and \(\text{KNO}_3\). Separate representative portions of the blend, each with a mass of \(3.085\text{ g}\), are analyzed as shown below.

| Analysis | Procedure | Measured result |
|—|—|—|
| Precipitation | The portion is dissolved, excess \(\text{AgNO}_3\text{(aq)}\) is added, and the precipitate is dried. | \(4.305\text{ g}\) of \(\text{AgCl(s)}\) |
| Thermal decomposition | The portion is heated until only \(\text{KNO}_3\) decomposes and the mass becomes constant. | Final mass of \(2.925\text{ g}\) |

The relevant processes are

\[
\text{Ag}^{+}\text{(aq)}+\text{Cl}^{-}\text{(aq)}\rightarrow\text{AgCl(s)}
\]

and

\[
2\,\text{KNO}_3\text{(s)}\rightarrow 2\,\text{KNO}_2\text{(s)}+\text{O}_2\text{(g)}.
\]

The relevant molar masses are \(M_{\text{NaCl}}=58.5\text{ g mol}^{-1}\), \(M_{\text{KCl}}=74.5\text{ g mol}^{-1}\), \(M_{\text{KNO}_3}=101.0\text{ g mol}^{-1}\), \(M_{\text{AgCl}}=143.5\text{ g mol}^{-1}\), and \(M_{\text{O}_2}=32.0\text{ g mol}^{-1}\). Which of the following gives the mole-percent composition of the original blend in the order \(\text{NaCl}\), \(\text{KCl}\), and \(\text{KNO}_3\)?

A student analyzes a solid salt blend recovered from a thermal-storage system. The blend contains only \(\text{NaCl}\), \(\text{KCl}\), and \(\text{KNO}_3\). Separate representative portions of the blend, each with a mass of \(3.085\text{ g}\), are analyzed as shown below.

| Analysis | Procedure | Measured result |
|---|---|---|
| Precipitation | The portion is dissolved, excess \(\text{AgNO}_3\text{(aq)}\) is added, and the precipitate is dried. | \(4.305\text{ g}\) of \(\text{AgCl(s)}\) |
| Thermal decomposition | The portion is heated until only \(\text{KNO}_3\) decomposes and the mass becomes constant. | Final mass of \(2.925\text{ g}\) |

The relevant processes are

\[
\text{Ag}^{+}\text{(aq)}+\text{Cl}^{-}\text{(aq)}\rightarrow\text{AgCl(s)}
\]

and

\[
2\,\text{KNO}_3\text{(s)}\rightarrow 2\,\text{KNO}_2\text{(s)}+\text{O}_2\text{(g)}.
\]

The relevant molar masses are \(M_{\text{NaCl}}=58.5\text{ g mol}^{-1}\), \(M_{\text{KCl}}=74.5\text{ g mol}^{-1}\), \(M_{\text{KNO}_3}=101.0\text{ g mol}^{-1}\), \(M_{\text{AgCl}}=143.5\text{ g mol}^{-1}\), and \(M_{\text{O}_2}=32.0\text{ g mol}^{-1}\). Which of the following gives the mole-percent composition of the original blend in the order \(\text{NaCl}\), \(\text{KCl}\), and \(\text{KNO}_3\)?

- **A.** \(25.0\%\), \(50.0\%\), \(25.0\%\)
- **B.** \(33.3\%\), \(66.7\%\), \(0.0\%\)
- **C.** \(50.0\%\), \(25.0\%\), \(25.0\%\)
- **D.** \(75.0\%\), \(0.0\%\), \(25.0\%\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/120115/*