some common alloys may include a nonmetal element

Answer 1

Hi Kenya B

The statement is true because:

A) To be an alloy, a mixture of elements must contain at least one metal, a condition that does not preclude the presence of non-metal elements.

B) Common examples include steel, the simplest form of which is composed of iron (metal) and carbon (non-metal), as well as aluminium alloys intended for casting which typically contain silicon (non-metal) as well as aluminium (metal).

Thats it, you only need to read what follows if you are curious.

The purpose of alloying is to adjust the natural properties of the metal you start with. In the case of steel, iron can have its ability to hold an edge much improved by mixing in some carbon. Metals in general are malleable and tend to deform rather than crack. The added carbons create a more rigid organization of atoms within the solid form of steel, leading to a more brittle solid that tends to resist deformation until it eventually cracks.

Similarly, mixing aluminium with silicon makes the solid structure of of aluminium less rigid, doing some of the work heat would normally have to do to melt it (since to become a liquid you have to break the rigid internal structure that makes it solid) and thus lowering the melting temperature. The addition of silicon also reduces the amount the material shrinks as it solidifies. Both properties are desirable for a casting material.

Hope this helps!

Joss