Question

A student creates three models to show how atoms are arranged in common substances. Model 1 represents iron, a solid metal that appears grey. Model 2 shows iron oxide, which forms when iron reacts with oxygen. Model 3 includes carbon along with iron oxide, appearing as a powder with black and brown particles.





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Which set of classifications and appearance descriptions would match the models?





A.
Model Classification Appearance
1 pure substance (element) uniform color
2 pure substance (compound) uniform color
3 heterogeneous (mixture) black and brown particles


B.
Model Classification Appearance
1 pure substance (compound) different colors
2 pure substance (element) different colors
3 homogeneous (mixture) black and brown particles


C.
Model Classification Appearance
1 pure substance (element) uniform color
2 heterogeneous (compound) different colors
3 heterogeneous (mixture) black and brown particles


D.
Model Classification Appearance
1 heterogeneous (element) different colors
2 pure substance (compound) uniform color
3 homogeneous (mixture) black and brown particles

Answer 1

A.

- Model 1: iron is an element (pure substance) and appears uniformly grey.
- Model 2: iron oxide is a compound (pure substance) and is a uniform rust color.
- Model 3: iron oxide mixed with carbon is a heterogeneous mixture (powder with distinct black and brown particles).