AP Chemistry
1.4 Composition of Mixtures
1.3 Elemental Composition of Pure Substances
1.1 Moles and Molar Mass
A student attempts to purify a sample of
\(\text{KNO}_3\) contaminated with
\(\text{NaNO}_3\) using fractional crystallization. To assess the purity of the recovered solid, the student performs elemental analysis on the dried product and compiles the theoretical and experimental data shown in the table below.
Which of the following statements correctly identifies whether the isolated solid is a pure substance or a mixture, and provides the valid justification?
\(\text{KNO}_3\) contaminated with
\(\text{NaNO}_3\) using fractional crystallization. To assess the purity of the recovered solid, the student performs elemental analysis on the dried product and compiles the theoretical and experimental data shown in the table below.
| Substance | Molar mass (\(\text{g/mol}\)) | Mass % \(\text{N}\) | Mass % \(\text{O}\) |
|---|---|---|---|
| Pure \(\text{KNO}_3\) | \(101.1\) | \(13.9\%\) | \(47.5\%\) |
| Pure \(\text{NaNO}_3\) | \(85.0\) | \(16.5\%\) | \(56.5\%\) |
| Isolated solid | — | \(15.2\%\) | \(52.0\%\) |
Which of the following statements correctly identifies whether the isolated solid is a pure substance or a mixture, and provides the valid justification?
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