Question

What evidence supports the notion that buckyballs are actual molecules and not extended materials? $$ \begin{array}{l}{\text { (a) Buckyballs are made of carbon. }} \\ {\text { (b) Buckyballs have a well-defined atomic structure and }} \\ {\text { molecular weight. }} \\ {\text { (c) Buckyballs have a well-defined melting point. }} \\ {\text { (a) Buckyballs are semiconductors. }} \\ {\text { (e) More than one of the previous choices. }}\end{array} $$

Short answer

The short answer is: \( \text{(e) More than one of the previous choices.} \)

Step-by-step solution

Evaluate statement (a)

Statement (a) states that buckyballs are made of carbon. This piece of information doesn't give us enough detail to determine whether they are molecules or extended materials since both types of materials can be made of carbon.

Evaluate statement (b)

Statement (b) claims that buckyballs have a well-defined atomic structure and molecular weight. This is a characteristic of molecules, as they have specific atomic structures and molecular weights, unlike extended materials (which do not have a specific molecular weight or structure). This statement supports the notion that buckyballs are actual molecules.

Evaluate statement (c)

Statement (c) states that buckyballs have a well-defined melting point. While this isn't a definitive characteristic of molecules, it does provide evidence that buckyballs possess a well-defined structure (which is consistent with being a molecule). This statement provides indirect support for the notion that buckyballs are actual molecules.

Evaluate statement (d)

Statement (d) claims that buckyballs are semiconductors. This fact doesn't provide evidence that can be used to determine whether buckyballs are molecules or extended materials. Both types of materials can act as semiconductors.

Choose the correct answer(s)

Reviewing the statements, we see that statements (b) and (c) provide evidence that supports the fact that buckyballs are actual molecules and not extended materials. As such, the correct answer choice is (e) - More than one of the previous choices.

Key concepts

Molecular Structure

Buckyballs are fascinating molecules that consist of 60 carbon atoms arranged in a highly symmetrical structure. This arrangement resembles a soccer ball and is known as a truncated icosahedron. The atomic structure is more than just visually appealing; it provides critical evidence that buckyballs, also known as fullerenes, have a well-defined molecular nature.

Unlike extended materials, which lack a fixed molecular structure, buckyballs are composed of a single type of atom (carbon) bonded together in a consistent 3D shape. This regular pattern is crucial because it allows for specific chemical and physical properties to emerge, which are unique to molecules.

Understanding the structure also helps to appreciate why buckyballs have particular characteristics, such as being able to encapsulate other molecules within their hollow centers. This makes them useful for applications ranging from drug delivery to materials science.

Molecular Weight

One of the definitive properties of molecules is their molecular weight, which refers to the mass of a molecule calculated by the sum of the atomic weights of its constituent atoms. For buckyballs, this is distinctly calculable because they consist of exactly 60 carbon atoms. The atomic weight of a carbon atom is approximately 12 amu (atomic mass units), so the molecular weight of a buckyball is around 720 amu.

This well-defined molecular weight differentiates buckyballs from extended materials, which do not have a consistent molecular composition and, thus, cannot be assigned a specific molecular weight. Knowing the molecular weight is fundamental for chemists because it helps in quantifying the amount of substance during chemical reactions.

Furthermore, this characteristic plays a crucial role in analyzing and supporting the fact that buckyballs are actual molecules. In research and applications, having an exact molecular weight aids in predicting how buckyballs will behave under different conditions, essential for their utility in various scientific fields.

Melting Point

The melting point is another important factor in determining the nature of a substance. Buckyballs possess a well-defined melting point, which provides evidence of their molecular structure. Having a specific melting point means they transition from a solid to a liquid at a known temperature, a property typical of molecular substances rather than extended materials.

For buckyballs, melting occurs at a relatively high temperature, which is consistent with their strong covalent bonds and stable structure. This stability is an indicator of their robustness and suitability for various applications where other materials might fail.

While the melting point alone isn't definitive proof that buckyballs are molecules, it is integral in supporting evidence due to the precise temperature range in which this change occurs. Such consistency and precision in melting behavior affirm that buckyballs are not just random structures but coherent molecular entities.