Question

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

Short answer

(a) Solid, Liquid, Gas (b) Gas, Liquid, Solid (c) Gas is most easily compressed.

Step-by-step solution

Understanding molecular disorder

Molecular disorder refers to the randomness of molecule arrangements in a substance. In general, as substances change state from solid to liquid to gas, their molecular disorder increases. This is because the particles in solids are closely packed together in a fixed arrangement, particles in liquids are also close together but are not in a fixed arrangement, and particles in gases are widely scattered and their arrangement is highly random.

Arranging states by increasing molecular disorder

Now that we understand that molecular disorder increases from solid to liquid to gas, we can easily list the states in order of increasing molecular disorder: 1. Solid 2. Liquid 3. Gas #b. Ordering states by intermolecular attraction#

Understanding intermolecular attraction

Intermolecular attraction refers to the force between the molecules in a substance. In general, these forces are stronger in solids, intermediate in liquids, and weakest in gases. This is because the particles in solids are closely packed together, particles in liquids are still close together but are not in a fixed arrangement, and particles in gases are widely scattered.

Arranging states by increasing intermolecular attraction

Now that we understand that intermolecular attraction is the strongest in solids, intermediate in liquids, and weakest in gases, we can easily list the states in order of increasing intermolecular attraction: 1. Gas 2. Liquid 3. Solid #c. Identifying the most easily compressed state#

Understanding compressibility

Compressibility is the ability of a substance to reduce its volume under applied pressure. When a substance is compressed, its particles are forced closer together. In general, gases are much more compressible than liquids and solids because the particles in gases are widely scattered and not already closely packed together like in liquids and solids.

Identifying the most easily compressed state

Now that we know that gases have the greatest compressibility, we can identify the most easily compressed state of matter: The most easily compressed state of matter is gas.

Key concepts

Molecular Disorder

Molecular disorder describes how unpredictably molecules are arranged within a substance. In solids, molecules are tightly packed and maintain a fixed, orderly structure. This means their arrangement is very predictable, resulting in low molecular disorder. As we transition to liquids, the molecules become less orderly. They are still close together but can move past one another, creating a more random structure compared to solids. This increases the molecular disorder. Lastly, gases exhibit the highest molecular disorder because the molecules are far apart, moving randomly and freely throughout the space. In summary, the order of states from least to most molecular disorder is:

• Solid
• Liquid
• Gas

Intermolecular Attraction

Intermolecular attraction refers to the forces of attraction between molecules in a substance. These forces play a vital role in defining the physical properties of a state of matter. In solids, molecules are held tightly together due to strong intermolecular forces. This close-packed arrangement results in high cohesive forces that keep the molecules in place. In liquid states, the intermolecular forces are weaker than in solids. While the molecules are still close, allowing for fluidity, they are not held rigidly, giving liquids an intermediate level of intermolecular attraction. Gases, on the other hand, have the least intermolecular attraction. Their molecules are spaced far apart, moving independently, which explains their weak intermolecular forces.
Hence, the order of states by increasing intermolecular attraction is:

• Gas
• Liquid
• Solid

Compressibility

Compressibility is the measure of how much a substance can be compacted under pressure. This characteristic significantly depends on the space between particles within a substance. Gases are highly compressible due to the large spaces between particles, allowing them to be compacted easily when pressure is applied. This attribute makes gases suitable for storage and transportation in smaller volumes. Liquids have much less compressibility compared to gases because their particles are considerably closer, limiting how much they can be squeezed together. Solids are the least compressible as their closely packed particles leave little room to adjust under pressure. As a result, the state of matter easiest to compress is:
Gas