Which of these statements about alloys and intermetallic compounds is false? (a) Bronze is an example of an alloy. (b) 'Alloy' is just another word for 'a chemical compound of fixed composition that is made of two or more metals.' (c) Intermetallics are compounds of two or more metals that have a definite composition and are not considered alloys. (d) If you mix two metals together and, at the atomic level, they separate into two or more different compositional phases, you have created a heterogeneous alloy. (e) Alloys can be formed even if the atoms that comprise them are rather different in size.

Verified step by step guidance

1. Identify the key terms: alloy, intermetallic compound, heterogeneous alloy, and compositional phases.
2. Understand that an alloy is a mixture of two or more elements, where at least one is a metal, and it does not have a fixed composition.
3. Recognize that intermetallic compounds have a definite stoichiometric composition and distinct crystal structures, unlike alloys.
4. Analyze each statement: (a) Bronze is a mixture of copper and tin, making it an alloy. (b) This statement incorrectly defines an alloy as a compound with a fixed composition. (c) Intermetallics are indeed compounds with definite compositions, not considered alloys. (d) A heterogeneous alloy has distinct phases, as described. (e) Alloys can form with atoms of different sizes, such as in substitutional or interstitial alloys.
5. Determine which statement is false based on the definitions and characteristics of alloys and intermetallic compounds.

Key Concepts

Alloys vs. Intermetallic Compounds

Alloys are mixtures of two or more metals that can exhibit variable compositions, while intermetallic compounds are distinct phases with a fixed stoichiometry. Alloys typically retain the properties of their constituent metals, whereas intermetallics often have unique properties that differ from those of the individual metals.

Heterogeneous vs. Homogeneous Alloys

A heterogeneous alloy consists of two or more distinct phases at the atomic level, meaning the metals do not mix uniformly. In contrast, a homogeneous alloy has a uniform composition throughout, where the metals are mixed at the atomic level, resulting in a single phase.

Composition and Properties of Alloys

The properties of an alloy depend on its composition and the relative sizes of the constituent atoms. Alloys can be formed even when the constituent metals have significantly different atomic sizes, which can lead to unique mechanical and physical properties, such as increased strength or corrosion resistance.