Question

Which characteristics of a solid, a liquid, and a gas are exhibited by each of the following substances? How would you classify each substance? a. a bowl of pudding b. a bucketful of sand

Short answer

A bowl of pudding exhibits characteristics of both solids and liquids, and is classified as a thick liquid or a semi-solid substance (colloidal suspension). A bucketful of sand behaves more like a solid, with characteristics of both solids and liquids, and can be classified as a granular material or a solid.

Step-by-step solution

Understanding Properties of Solids, Liquids, and Gases

In order to classify the given substances, it is important to know the typical properties of solids, liquids, and gases. Solids have a fixed shape and a fixed volume, their particles are tightly packed, and they do not flow easily. Liquids have a fixed volume, but their shape depends on their container. Their particles have more freedom of movement compared to solids, and they can flow easily. Gases do not have a fixed shape or volume, and their particles move freely and spread out to occupy their container. Gases also flow and compress easily.

Analyzing a Bowl of Pudding

A bowl of pudding exhibits some characteristics of both solids and liquids. It has a semi-fixed shape, depending on the shape of the container it is in, and a fixed volume. The particles are closer together than in a gas. Pudding can flow, but not as easily as water or other common liquids. When classifying pudding, it is considered a thick liquid or a semi-solid substance, more commonly labeled as a "colloidal suspension." Meaning it has fine solid particles dispersed in a liquid medium.

Analyzing a Bucketful of Sand

A bucketful of sand does not have a fixed shape but takes the shape of the container, similar to liquids. However, it has a fixed volume like a solid, and its particles are tightly packed together. Sand does not flow easily but can be poured, which is a characteristic of both solids and liquids. When classifying sand, we can consider it a granular material or a collection of solid particles, but it behaves more like a solid in general.

Classification of the Substances

Based on their characteristics, we can classify the given substances as follows: a. A bowl of pudding is classified as a thick liquid or a semi-solid substance (colloidal suspension). b. A bucketful of sand can be classified as a granular material or a solid, as it has more characteristics of a solid compared to a liquid.

Key concepts

Understanding the Solid State

The solid state is characterized by a specific set of properties that define its rigidity and structure. \[\text{\(1)\)}\] Solids have a fixed shape, meaning that without any external force, they maintain their form and do not adapt to the shape of a container. \[ \text{\(2)\)} \] They also have a fixed volume, indicating that the space they occupy remains constant under normal conditions.
These features develop due to the tightly packed particles that make up a solid. The particles are arranged in a specific structure, often a lattice, that restricts their movement to mere vibrations in fixed positions.
This arrangement provides solids with rigidity and the ability to withstand forces without altering their shape readily.

• Examples include metals like iron and copper, as well as non-metals like diamond and wood.
• Solids have high density compared to liquids and gases due to closely packed particles.
• They do not compress easily, as there's little space between particles to allow compression.

Exploring the Liquid State

Liquids possess a unique set of attributes that differentiate them from solids and gases. \( \text{\(1)\)} \) They maintain a fixed volume but take on the shape of their container. This means they can flow and adapt, yet their intrinsic volume remains unchanged. In a liquid, particles are still close together, but they have more freedom compared to solids. This allows them to move around and slide past each other.
This capability to flow makes liquids vital for many everyday applications, like filling containers, pouring, and transferring heat. Liquids exhibit surface tension, which is the tendency for the surface of a liquid to contract and resist being penetrated.

• Water, oil, and alcohol are common examples of liquids.
• Liquids have a moderate density; higher than gases but lower than solids.
• They are not easily compressed because the particles are closely packed but not as tightly as in a solid.

Diving into the Properties of Gases

Gases are characterized by their complete lack of fixed shape or volume, setting them apart from solids and liquids. Their particles move independently and fill the entirety of any given container, irrespective of its size. \( \text{\(1)\)} \) Gases are highly compressible, which means their volume can be significantly reduced when pressure is applied, unlike solids and liquids. This is because there is considerable space between gas particles.
\( \text{\(2)\)} \) Gases are in constant random motion, contributing to their ability to flow and spread rapidly, a property known as diffusion.
This feature makes gases essential in applications such as air conditioning, breathing (oxygen), and cooking (natural gas).

• Common examples include oxygen, carbon dioxide, and nitrogen.
• Gases have the lowest density among the three states of matter.
• Their volume and shape are variable, adjusting easily to the shape and size of their containers.