Question

A fluorocarbon, \(\mathrm{CF}_{4},\) has a critical temperature of -45.7 \(^{\circ} \mathrm{C}\) and a critical pressure of 37 atm. Are there any conditions under which this compound can be a liquid at room temperature? Explain briefly.

Short answer

No, CF_{4} cannot be a liquid at room temperature because room temperature is above its critical temperature.

Step-by-step solution

Understanding the Concept of Critical Temperature

The critical temperature ( TC ) is the highest temperature at which a substance can exist as a liquid, regardless of pressure. For CF_{4} , the critical temperature is -45.7^{ ext{ orddater}}C . This means that above this temperature, CF_{4} cannot be a liquid and will always remain in the gaseous state, no matter how much pressure is applied.

Determining Room Temperature

Room temperature is typically around 20^{ ext{}}C to 25^{ ext{}}C . This temperature is considerably higher than the critical temperature of -45.7^{ ext{}}C for CF_{4} .

Analyzing if CF_{4} Can Be a Liquid at Room Temperature

Since room temperature ( 20^{ ext{}}C to 25^{ ext{}}C ) is significantly higher than the critical temperature of -45.7^{ ext{}}C , CF_{4} cannot be a liquid at room temperature. At any temperature above its critical temperature, a substance can only exist as a gas, regardless of the pressure applied.

Key concepts

Fluorocarbon

Fluorocarbons are chemical compounds that consist of carbon and fluorine atoms. They are well known for their unique properties, such as high chemical stability and non-flammability. These compounds are widely used in refrigeration, pharmaceuticals, and as solvents in various industrial applications. What makes fluorocarbons particularly interesting is their ability to serve as refrigerants due to their low boiling points and inert nature. However, their environmental impact, especially concerning ozone depletion and global warming potential, needs to be monitored and regulated.
Understanding fluorocarbons like tetrafluoromethane (CF4) is important, as it helps us better appreciate the nuances of their physical state changes under different conditions; especially how temperature and pressure affect these states. Familiarity with these properties can help when working with these substances in practical applications.

CF4

CF4, or tetrafluoromethane, is one of the simplest members of the fluorocarbons family. It has one carbon atom surrounded by four fluorine atoms, forming a stable and symmetric structure. This compound is colorless, odorless, and does not easily react with other substances. However, it occupies a critical role in understanding gas behaviors due to its distinct physical properties.
CF4 has a particularly low critical temperature, meaning its ability to transition into a liquid is limited to a narrow range of conditions. Its critical temperature is only \(-45.7^{\circ}C\) indicating that beyond this temperature it remains in the gaseous state regardless of pressure. Thus, when examining environmental or industrial contexts, knowledge of CF4’s critical temperature is crucial for determining how it can be employed or stored.

Gaseous State

The gaseous state is a phase of matter characterized by molecules that are far apart and moving freely. In this state, substances assume the volume and shape of their containers. This is different from solids and liquids, where particles are much closer and have specific structures. Tetrafluoromethane (CF4) is often found in the gaseous state under normal environmental conditions due to its low boiling point and critical temperature. For substances like CF4, this means that they are gaseous at room temperature, around \(20^{\circ}C\) to \(25^{\circ}C\), and any conditions exceeding their critical temperature will maintain its gaseous state despite changes in pressure. Understanding why CF4 cannot be a liquid in such conditions helps in designing equipment and processes that account for its persistent gaseous nature, ensuring efficiency and safety in applications like electronics manufacturing or refrigeration.

Concept of Temperature-Pressure Relationship

The relationship between temperature and pressure is a fundamental concept in thermodynamics, significantly impacting the behavior of gases. At high temperatures, gases expand and can exert greater pressure, whereas at lower temperatures, they condense if enough pressure is applied. Critical temperature is a key point in understanding this relationship, marking the maximum temperature at which a substance can exist as a liquid under any pressure. For CF4, with its critical temperature of \(-45.7^{\circ}C\), it means room temperature conditions are far above this limit, preventing it from becoming liquid regardless of increases in pressure. The temperature-pressure relationship explains why increasing pressure cannot liquefy CF4 at ordinary temperatures, as the temperature still exceeds its critical threshold. This concept is crucial in fields that manage gases and require precise control under varying temperatures and pressures, such as chemical engineering and environmental science.