Question

List the three states of matter in order of (a) increasing molecular disorder and (b) increasing intermolecular attractions. (c) Which state of matter is most easily compressed?

Short answer

(a) Increasing molecular disorder: solid, liquid, gas. (b) Increasing intermolecular attractions: gas, liquid, solid. (c) The state of matter that is most easily compressed: gas.

Step-by-step solution

Identify the three states of matter

The three states of matter are solid, liquid, and gas.

Order states based on increasing molecular disorder

Molecular disorder refers to the randomness or chaos of molecules in a substance. The order based on increasing molecular disorder is solid, liquid, and gas. In a solid, molecules are arranged in a fixed pattern and have the least disorder. In a liquid, molecules have more freedom of movement and are more disorganized than in a solid. In a gas, molecules move most randomly and have the maximum disorder.

Order states based on increasing intermolecular attractions

Intermolecular attractions refer to the forces between molecules in a substance. The order based on increasing intermolecular attractions is gas, liquid, and solid. In a gas, molecules are far apart and have the weakest intermolecular attractions. In a liquid, molecules are closer together and have stronger intermolecular attractions than gases. In a solid, molecules are closely packed and have the strongest intermolecular attractions of the three states.

Determine which state is most easily compressed

Compressibility refers to the ability of a substance to change its volume under pressure. Gases are the most easily compressed states of matter because their molecules are far apart, and applying pressure can bring them closer together without much resistance. So the answers are: (a) Increasing molecular disorder: solid, liquid, gas. (b) Increasing intermolecular attractions: gas, liquid, solid. (c) The state of matter that is most easily compressed: gas.

Key concepts

Molecular Disorder

The concept of molecular disorder, also known as entropy, plays a vital role in understanding the behavior of substances in different states of matter. Molecular disorder is the degree to which molecules within a substance are arranged randomly or exhibit chaotic motion. In the solid state, molecules are tightly bound in a structured lattice, exhibiting low levels of entropy due to their uniform arrangement and limited movement. As matter transitions to a liquid state, this structured organization is disrupted, and molecules have increased freedom to move around, resulting in higher molecular disorder. Lastly, in the gaseous state, molecules break free from any long-range order and move freely in the container, demonstrating the highest degree of entropy among the three states.

Understanding molecular disorder helps to explain why substances change states at different temperatures and pressures, as these conditions can influence the entropy of a system. For instance, heating a solid often provides enough energy for molecules to overcome their rigid arrangement, thus increasing the molecular disorder and causing the solid to melt into a liquid. Continued heating can then turn the liquid into a gas, where the molecules exhibit maximum disorder due to significant separation from each other.

Intermolecular Attractions

Intermolecular attractions are the forces that exist between molecules, contributing to the physical properties of a substance. These attractions help in determining the state of matter of a substance at a given temperature and pressure. In gases, the molecules are widely spaced and move rapidly, which results in weak intermolecular forces and thus, low attraction. Because the molecules are so far apart, they barely interact with one another.

In liquids, the situation is quite different. The molecules are closer together than in gases, allowing for stronger intermolecular attractions. These forces are dynamic, however, as molecules still have the ability to move around each other, which accounts for the flowing nature of liquids.

Solids feature the strongest intermolecular attractions. The molecules are closely packed in a fixed arrangement, typically in a crystal lattice. It is this tight packing and the significant forces of attraction that keep the molecules in place, resulting in a rigid structure. Understanding these attractions is essential when one considers the melting and boiling points of different substances; higher intermolecular forces generally mean higher temperatures are required to change state.

Compressibility of Matter

Compressibility is a measure of how much the volume of matter decreases under applied pressure. It reveals interesting aspects about the spacing and interactions between particles in different states. Gases are highly compressible as compared to liquids and solids because of the large amount of empty space between their molecules. When pressure is applied, gas molecules, which are in constant motion and far apart, are forced closer together, thus reducing the volume of the gas significantly.

Liquids have much less compressibility since their molecules are already relatively close together. Applying pressure to a liquid will only negligibly decrease its volume as the molecules have little room to move closer. Solids are the least compressible state of matter due to their tightly packed molecules that resist any changes in their arrangement. This resistance to compression explains the fixed shape and volume of solids, essential properties that distinguish solids from liquids and gases.

The understanding of compressibility not only aids in identifying the state of matter but also has practical applications across various industries, such as in the design of pressure vessels and in understanding the behavior of gases within the earth's atmosphere.