Mixture Chemistry Example 3

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Example 3

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Explain why mixing iron filings and sulfur powder produces a mixture, but heating them together produces a compound (FeS\text{FeS}). How could you distinguish between the two?

Solution

  1. 1
    When mixed without heating, iron and sulfur retain their individual properties — iron can be removed with a magnet, and sulfur can be dissolved in carbon disulfide. This is a mixture.
  2. 2
    When heated, they undergo a chemical reaction (Fe+SFeS\text{Fe} + \text{S} \rightarrow \text{FeS}), forming a new substance that is non-magnetic and has different properties from either element.

Answer

Mixture: separated by magnet. Compound (FeS): non-magnetic, new properties.\text{Mixture: separated by magnet. Compound (FeS): non-magnetic, new properties.}
This classic experiment demonstrates the difference between physical mixing and chemical combination. The compound FeS has properties entirely different from iron and sulfur, confirming that a chemical change occurred.

About Mixture

A physical combination of two or more substances that are not chemically bonded, retain their individual properties, exist in variable proportions, and can be separated.

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