Question

A diagram in a chemistry book shows a magnified view of a flask of air as follows: What do you suppose is between the dots (the dots represent air molecules)? a. air b. dust c. pollutants d. oxygen e. nothing

Short answer

The correct answer is e) nothing, as the spaces between air molecules (dots) in a flask of air are empty and not occupied by any substance, dust, or pollutant.

Step-by-step solution

Understand the composition of air

Air is a mixture of different gases, with nitrogen and oxygen being the main components (about 78% nitrogen, 21% oxygen). The remaining 1% is composed of other gases such as argon, carbon dioxide, water vapor, and trace amounts of other gases. Also, keep in mind that air is not a pure substance.

Analyze the spaces between air molecules

In a flask of air, the air molecules (such as nitrogen and oxygen molecules) are in constant motion. They don't take up all the space in the flask, and as a result, there is empty space between them.

Evaluate the options in the context of the flask of air

Considering the composition of air and the spaces between air molecules in the flask, let's evaluate the options: a) Air: This option is not suitable as the mixture of air gases already represented by the dots. b) Dust: While dust might be present in the air, it's not typically found in the spaces between air molecules. c) Pollutants: Pollutants can exist in a flask of air, but these substances are still part of the air mixture and not necessarily found specifically between air molecules. d) Oxygen: Oxygen is one of the main components of air and hence is already represented by the dots. e) Nothing: This is the best option, as it signifies the empty space between the nitrogen and oxygen molecules that make up air.

Conclusion

The correct answer to the question "What do you suppose is between the dots (air molecules)?" is e) nothing, as the empty space between air molecules is not occupied by any substance, dust, or pollutant.

Key concepts

Air Molecules

Air isn't just empty space; it's a dynamic and invisible mixture filled with tiny particles known as air molecules. When we look at a magnified view of air in a container, it's essential to understand that these air molecules are mostly nitrogen, oxygen, and small amounts of other gases. Each molecule is constantly in motion due to the energy it possesses.

This continuous movement means that molecules collide and bounce off each other, which leaves gaps between them. These gaps are often misunderstood and might seem like they contain air or other substances, but in reality, except for the occasional passage of other air molecules, they are empty spaces. Grasping this concept is pivotal to understanding the nature of gases and the true composition of air.

Properties of Gases

Gases have unique properties that differentiate them from solids and liquids. Primarily, gases are compressible, meaning they can be pressed into a smaller volume. This is possible because of the space between air molecules we've discussed previously. Another property is their ability to fill a container completely, taking the shape of the container they are in.

Moreover, the molecules in a gas move rapidly and in all directions, which is referred to as random motion. Due to this behavior, they exert pressure on the walls of their container; this pressure is a result of molecules colliding with the container's surfaces. Also, their movement means that gases can mix evenly and completely when put together. Understanding these properties helps explain why 'nothing' is indeed between the air molecules — there is no physical structure that maintains a shape or volume without the container.

Mixture of Gases

The air that surrounds us is a mixture of different gases, each contributing to the overall makeup of Earth's atmosphere. The primary gases, nitrogen and oxygen, make up about 99% of clean, dry air. However, there are also small quantities of other gases, such as argon, carbon dioxide, and neon, as well as variable amounts of water vapor.

This complex mixture is not a compound; there are no chemical bonds holding the different gases together. They are simply coexisting in the same space and can be separated through physical means. One might think of air as a buffet of different gases, where each gas retains its individual properties even while blending seamlessly to form what we breathe. The comprehension that air is this mixture of gases, rather than a single substance, is essential in understanding atmospheric composition and behavior.