Question

Describe the color of oxygen in the liquid state.

Short answer

Liquid oxygen is pale blue.

Step-by-step solution

Understanding Oxygen States

Oxygen is typically a clear gas under normal conditions at room temperature. However, when cooled to extremely low temperatures, oxygen can exist in a liquid form. In its liquid state, it displays a distinct color.

Observing Liquid Oxygen

Liquid oxygen is obtained by cooling gaseous oxygen below its boiling point, which is approximately -183°C (-297°F). As it transitions from gas to liquid, its appearance changes.

Identifying the Color

The color of liquid oxygen is a pale blue. This is a result of its molecular structure and light absorption properties that give it this characteristic hue.

Key concepts

Oxygen Properties

Oxygen is an essential element found in the Earth's atmosphere and is crucial for the survival of most living organisms. It is represented by the symbol \( O_2 \) in its molecular form. Here are a few key properties of oxygen:

• At room temperature, oxygen is a colorless, tasteless, and odorless gas. It constitutes about 21% of Earth's atmosphere.
• Oxygen is highly reactive and forms compounds with most other elements. It is part of important compounds such as water (\( H_2O \)) and carbon dioxide (\( CO_2 \)).
• Oxygen supports combustion, which means it is essential for the process of burning.

Understanding these basic properties helps in grasping why oxygen behaves differently in its various states of matter.

States of Matter

Matter can exist in different states: solid, liquid, and gas. These are also known as phases of matter, and each state has unique characteristics depending on the arrangement and energy of the particles:

• Solid: Atoms or molecules are tightly packed in a fixed arrangement. Solids have a definite shape and volume.
• Liquid: Molecules are close but not in a fixed pattern, allowing liquids to flow and take the shape of their container while maintaining a definite volume.
• Gas: Particles are widely spaced and move freely, resulting in no definite shape or volume. Gases always expand to fill their containers.

In the case of oxygen, it transitions from a gaseous state to a liquid state when sufficiently cooled. This change in state results in observable differences, including a distinct color change.

Color of Elements

The color of an element in different states can vary dramatically due to changes in molecular arrangement and interaction with light. For example, liquid oxygen displays a pale blue color. This specific hue results from oxygen's unique molecular properties:

• In its liquid form, the oxygen molecules absorb light in the red spectrum. This absorption gives liquid oxygen its blue tint, as it scatters the remaining wavelengths of light, which are blue in color.
• The interaction of light with the electrons in the oxygen molecules leads to this absorption, showcasing the impact of molecular structure on color.

Colors of elements can provide insights into their properties and behaviors, particularly interactions with different energies or states.