Video Transcript
Which of the following is the best
description of an alloy? (A) A solid solution of one or more
elements within a pure metal. (B) A mixture of two or more
nonmetals. (C) A pure metal. (D) The product of smelting. Or (E) a material made by
alternating layers of different materials.
To answer this question, we need to
determine which of the answer choices is the best description of an alloy.
To help us determine which of the
answer choices is correct, let’s take a closer look at two alloys, brass and
steel. Brass is an alloy composed of about
30 percent zinc and 70 percent copper, two different metals. If we zoomed in on the lattice
structure, we would see that the zinc atoms are irregularly distributed throughout
the copper atoms. The mixture of zinc with copper
produces a metal that is more malleable than both zinc or copper alone. Steel is an alloy produced by
mixing a relatively low percentage of carbon with iron. If we zoomed in on the atoms, we
would see that the carbon atoms are irregularly dispersed in between the iron
atoms. The mixture of carbon with iron
produces a metal that is very strong and highly resistant to most forms of
corrosion. Now that we’ve examined two alloys,
let’s take a look at the answer choices.
Answer choice (A) states that an
alloy is a solid solution of one or more elements within a pure metal. Both brass and steel are solid
solutions. Each consists of an element within
a pure metal. So answer choice (A) appears to be
the correct answer. But just to be sure, let’s take a
look at the other answer choices.
Answer choice (B) states that an
alloy is a mixture of two or more nonmetals. While carbon is a nonmetal, zinc,
copper, and iron are all metals. So answer choice (B) cannot be the
answer to this question.
We already know that alloys like
brass and steel are a mixture of two or more substances. So an alloy cannot be a pure
metal.
Smelting is the process of
extracting a metal from its ore. Smelting can be used to extract
metals like copper and iron from their ores. But in order to produce brass and
steel, these metals must be mixed with other substances in a process called
alloying. As the product of smelting is a
base metal, not an alloy, answer choice (D) cannot be the answer to this
question.
Answer choice (E) states that an
alloy is a material made by alternating layers of different materials. We can see from the arrangement of
the atoms in an alloy that the atoms are irregularly dispersed, not layered. Thus, answer choice (E) is not the
answer to this question.
Therefore, the best description of
an alloy is answer choice (A), a solid solution of one or more elements within a
pure metal.
