Question

Which of the following are observed general properties of solids? (a) fixed shape (b) crystalline structure (c) do not compress (d) less dense than liquids

Short answer

Solids generally have a fixed shape, can be crystalline, and are difficult to compress; they are typically more dense than liquids.

Step-by-step solution

Understanding Solids

Solids are one of the states of matter that are characterized by a definite shape and volume. This means they do not flow like liquids or gases. As such, one property commonly associated with solids is that they have a fixed shape.

Analyzing Crystalline Structure

Many solids are crystalline, meaning they are composed of crystals that are arranged in a highly ordered, repeating pattern. Not all solids are crystalline, however, and some are amorphous, which makes their structure less ordered.

Exploring Compressibility

Solids are often described as being incompressible because their particles are closely packed together, leaving very little space to be compressed further. Unlike gases, their volume does not change significantly under pressure.

Comparing Density with Liquids

Solids generally have a higher density compared to liquids because the particles are more tightly packed. This means that solids are usually more dense rather than less dense than liquids.

Key concepts

States of Matter

Matter exists in different states, the most familiar of which are solids, liquids, and gases. Solids have a distinct arrangement that causes them to maintain a fixed shape and volume, unlike liquids that can flow and assume the shape of their container, or gases that expand to fill available space. Solids do not flow because their particles are closely packed in a fixed, rigid arrangement, which dictates their set volume and shape. This is why a book remains a rectangle whether it is on a desk or a shelf—this stable form is characteristic of the solid state of matter.

Crystalline vs Amorphous Solids

Solids can be categorized as crystalline or amorphous based on their internal structure. Crystalline solids have atoms or molecules arranged in a highly ordered, repeating pattern, like the neat stacks of a brick wall. This ordered structure results in unique properties like distinct melting points and the ability to produce clear, defined crystal shapes.

• Examples of crystalline solids are salt, diamonds, and sugar.

Amorphous solids, on the other hand, do not possess such a neat and orderly structure. Their particles are not arranged in a regular pattern, leading to different physical properties.

• Common examples include glass and plastics, which do not have a sharp melting point but soften over a range of temperatures.

Thus, understanding the differences between crystalline and amorphous solids helps in predicting and explaining their behavior.

Compressibility of Solids

An important property of solids is their low compressibility compared to liquids and gases. In solids, particles are packed so tightly together that there is minimal space for them to move closer. This means applying pressure to a solid does not significantly change its volume, unlike gases that are highly compressible due to large intermolecular spaces. On the other hand, liquids have particles that are less tightly packed than solids but not as free as gases, making them slightly compressible. For example, squeezing a sponge filled with water expels more of the liquid than changes the sponge's own volume. Understanding this concept explains why solids are used to build structures—they do not easily deform under pressure, providing stability and strength to the objects around us.