---
title: "A student analyzes a 10.00 g solid mixture containing only \\(\\text{FeO(s)}\\) and \\(\\text{Fe}_2\\text{O}_3\\text{(s)}\\). The mixture is heated in a stream of excess \\(\\text{H}_2\\text{(g)}\\) until both iron oxides are completely reduced to elemental iron according to the following chemical equations:  \\[\\text{FeO(s)} + \\text{H}_2\\text{(g)} \\rightarrow \\text{Fe(s)} + \\text{H}_2\\text{O(g)}\\] \\[\\text{Fe}_2\\text{O}_3\\text{(s)} + 3\\text{ H}_2\\text{(g)} \\rightarrow 2\\text{ Fe(s)} + 3\\text{ H}_2\\text{O(g)}\\]  After the reaction is complete and the tube is cooled, the remaining solid iron has a mass of \\(7.35 \\text{ g}\\).  | Substance | Molar Mass (\\(\\text{g/mol}\\)) | |—|—| | \\(\\text{Fe}\\) | 56.0 | | \\(\\text{O}\\) | 16.0 | | \\(\\text{FeO}\\) | 72.0 | | \\(\\text{Fe}_2\\text{O}_3\\) | 160. |  Given the information in the table above, what is the mass percent of \\(\\text{FeO(s)}\\) in the original mixture?"
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url: "https://nerd-notes.com/ubq/119545/"
date_modified: "2026-08-21T03:26:47+00:00"
---

# A student analyzes a 10.00 g solid mixture containing only \(\text{FeO(s)}\) and \(\text{Fe}_2\text{O}_3\text{(s)}\). The mixture is heated in a stream of excess \(\text{H}_2\text{(g)}\) until both iron oxides are completely reduced to elemental iron according to the following chemical equations:

\[\text{FeO(s)} + \text{H}_2\text{(g)} \rightarrow \text{Fe(s)} + \text{H}_2\text{O(g)}\]
\[\text{Fe}_2\text{O}_3\text{(s)} + 3\text{ H}_2\text{(g)} \rightarrow 2\text{ Fe(s)} + 3\text{ H}_2\text{O(g)}\]

After the reaction is complete and the tube is cooled, the remaining solid iron has a mass of \(7.35 \text{ g}\).

| Substance | Molar Mass (\(\text{g/mol}\)) |
|—|—|
| \(\text{Fe}\) | 56.0 |
| \(\text{O}\) | 16.0 |
| \(\text{FeO}\) | 72.0 |
| \(\text{Fe}_2\text{O}_3\) | 160. |

Given the information in the table above, what is the mass percent of \(\text{FeO(s)}\) in the original mixture?

A student analyzes a 10.00 g solid mixture containing only \(\text{FeO(s)}\) and \(\text{Fe}_2\text{O}_3\text{(s)}\). The mixture is heated in a stream of excess \(\text{H}_2\text{(g)}\) until both iron oxides are completely reduced to elemental iron according to the following chemical equations:

\[\text{FeO(s)} + \text{H}_2\text{(g)} \rightarrow \text{Fe(s)} + \text{H}_2\text{O(g)}\]
\[\text{Fe}_2\text{O}_3\text{(s)} + 3\text{ H}_2\text{(g)} \rightarrow 2\text{ Fe(s)} + 3\text{ H}_2\text{O(g)}\]

After the reaction is complete and the tube is cooled, the remaining solid iron has a mass of \(7.35 \text{ g}\).

| Substance | Molar Mass (\(\text{g/mol}\)) |
|---|---|
| \(\text{Fe}\) | 56.0 |
| \(\text{O}\) | 16.0 |
| \(\text{FeO}\) | 72.0 |
| \(\text{Fe}_2\text{O}_3\) | 160. |

Given the information in the table above, what is the mass percent of \(\text{FeO(s)}\) in the original mixture?

- **A.** \(35.0\%\)
- **B.** \(45.0\%\)
- **C.** \(55.0\%\)
- **D.** \(73.5\%\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119545/*