Alloys, such as brass, are pure substances.

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anonymous · Answer

http://upload.wikimedia.org/wikipedia/commons/thumb/5/5a/Alloy_atomic_arrangements_showing_the_different_types.jpg/350px-Alloy_atomic_arrangements_showing_the_different_types.jpg No. The whole point of an alloy is that you put DIFFERENT elements in for increased strength.

anonymous · Answer

The composition of an alloy can usually vary within a range.  Gold, for example, is frequently allowed with silver or copper from 75% (14 karat gold) to 42% (10 karat gold).  Normally we don't call a mixture (or really a solution) that can vary like this a "pure substance."  You're better off calling it a solution, or mixture.