Question

Make a drawing, based on the kinetic-molecular theory and the ideas about atoms and molecules presented in this chapter, of the arrangement of particles in each of the cases listed here. For each case, draw 10 particles of each substance. It is acceptable for your diagram to be two dimensional. Represent each atom as a circle, and distinguish each different kind of atom by shading. (a) a sample of solid iron (which consists of iron atoms) (b) a sample of liquid water (which consists of \(\mathrm{H}_{2} \mathrm{O}\) molecules) (c) a sample of water vapor

Short answer

Solid iron: tightly packed atoms; liquid water: close clusters of H2O; water vapor: spread out clusters of H2O.

Step-by-step solution

Understand the Kinetic-Molecular Theory

Kinetic-molecular theory explains the behavior of particles in different states of matter: solids, liquids, and gases. In solids, particles are tightly packed with very little movement. In liquids, particles are more spaced out and can move around each other. In gases, particles are spread out and move freely and rapidly.

Visualize Solid Iron

Solid iron consists of iron atoms closely packed together in a regular pattern. Draw 10 tightly packed circles to represent the iron atoms. You can shade them all the same to distinguish them as one type of atom. Ensure no spaces between circles, reflecting the rigid structure of a solid.

Visualize Liquid Water

Liquid water consists of water molecules ( H_2O ), each made of one oxygen atom and two hydrogen atoms. Draw 10 clusters of three circles, with one representing oxygen and two smaller ones for hydrogen. Position these clusters close but more disordered than the solid. You can shade differently for oxygen and hydrogen to differentiate.

Visualize Water Vapor

In water vapor, water molecules are far apart and move freely. Draw 10 clusters of three circles, as in liquid water, but spread them throughout the space with significant distance between each cluster, indicating freedom of movement. Different shading should again distinguish oxygen from hydrogen.

Key concepts

States of Matter

The states of matter are three fundamental phases in which substances exist: solids, liquids, and gases. These states display different properties and behaviors based on the arrangement and movement of their particles. In solids, atoms or molecules are packed closely in a fixed pattern, forming a rigid and stable structure. This gives solids a definite shape and volume. In liquids, the particles are still close but not in a fixed position, which allows them to flow and take the shape of their container while maintaining a constant volume. Finally, gases have particles that are far apart and move freely, leading to no fixed shape or volume. Gases can expand to fill any container, unlike solids and liquids.
Understanding these states requires examining how closely the particles are arranged and how they move in each state. By grasping these differences, we can explain how iron remains hard and strong or how water can flow and evaporate.

Particle Arrangement

The arrangement of particles varies widely across the three states of matter. In a solid, for instance, particles are arranged in a tight, orderly fashion. This formation is known as a crystal lattice when considering a crystalline solid like iron. This structured arrangement restricts the movement of the particles, causing solids to be firm and preserving their shape.

In liquid matter, such as water, the particles are packed less tightly than in solids. There is enough space between them to slide past each other, which grants liquids the ability to flow and adapt to the shape of their container. Their arrangement is more random compared to the fixed lattice of solids, giving liquids a fluid nature.
For gaseous substances, the particles are dispersed with considerable distance between them. They move rapidly and independently, leading to random arrangements. This particle separation explains why gases fill any volume and are easily compressed. These distinct arrangements are why the matter appears and behaves so differently in each state.

Solids, Liquids, and Gases

Solids, liquids, and gases are all vital forms of matter observed in everyday life. Each possesses unique characteristics due to their distinct particle behavior. For example, solid iron is composed of iron atoms arranged in a dense and orderly manner, resulting in its solid form and ability to maintain shape.

Liquid water, on the other hand, consists of molecules made from two hydrogen atoms bonded to one oxygen atom ( H_2O ). The water molecules are more loosely arranged than in solids, allowing them to move around fluidly. This feature is why water can pour and take the shape of whatever container it is in.
In contrast, water vapor, the gaseous form of water, consists of the same H_2O molecules as liquid water, but they are widely spaced and move freely. This level of freedom results in vapor dispersing quickly and filling available space, such as when steam escapes from a pot. Each state has its distinct traits, making solids hard, liquids flexible, and gases expansive.