Question 15

A penny made only of copper would be classified as a pure substance that is an element.

A penny composed solely of copper qualifies as a pure substance and specifically as an element because it consists entirely of copper atoms, without any other substances mixed in.

A) heterogeneous mixture of two compounds

This option is incorrect because a heterogeneous mixture consists of two or more substances that are not uniform in composition. A penny made only of copper does not contain multiple compounds; it is a single kind of material.

B) pure substance that is an element

This option is correct because copper is classified as an element on the periodic table, and a penny made entirely of copper consists only of copper atoms, making it a pure substance.

C) homogeneous mixture of two elements

This option is incorrect as a homogeneous mixture contains two or more substances that are uniformly distributed. A penny made only of copper does not contain different elements mixed together; it is entirely composed of one element.

D) pure substance that is a compound

This option is incorrect because a compound is formed when two or more different elements are chemically combined. Since a penny made only of copper contains only one element, it cannot be classified as a compound.

Conclusion

The correct classification of a penny made solely of copper is as a pure substance that is an element, as it consists entirely of copper atoms. All other options fail because they either mischaracterize the nature of the material or incorrectly describe its composition, which does not involve multiple elements or compounds.