Pure substances can be elements or compounds. An element is a form of matter which cannot be broken down by chemical reactions into simpler substances. A compound is a substance composed of two or more different types of elements, chemically combined in a fixed proportion. Properties of a compound are different from its constituent elements, whereas a mixture shows the properties of its constituting elements or compounds
The substance formed by mixing, crushing and heating iron filings and sulphur powder is

Options

A. an element
B. a compound
C. a mixture
D. a solution.

Explanation

To determine the substance formed by mixing, crushing, and heating iron filings and sulphur powder, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Components**: The two components involved are iron filings (Fe) and sulphur powder (S).

2. **Understand the Process**: The process described involves mixing, crushing, and heating these two substances. This indicates that a chemical reaction is likely taking place.

3. **Chemical Reaction**: When iron and sulphur are heated together, they undergo a chemical reaction to form a new substance. This reaction can be represented by the equation:
\[ \text{Fe} + \text{S} \rightarrow \text{FeS} \]
Here, FeS is ferrous sulphide.

4. **Classify the Resulting Substance**: The product formed, FeS (ferrous sulphide), is a compound. A compound is defined as a substance that consists of two or more different elements that are chemically combined in a fixed ratio.

5. **Properties of the Compound**: The properties of ferrous sulphide (FeS) are different from those of its constituent elements (iron and sulphur). This is a characteristic feature of compounds.

6. **Conclusion**: Therefore, the substance formed by mixing, crushing, and heating iron filings and sulphur powder is ferrous sulphide (FeS), which is a compound.

### Final Answer:
The substance formed by mixing, crushing, and heating iron filings and sulphur powder is **ferrous sulphide (FeS)**.

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