Question

In the liquefaction process, why are gases compressed to very high pressures?

Short answer

Answer: Gases are compressed to very high pressures during the liquefaction process to increase their density, make them easier to store and transport, and to bring gas molecules closer together. This enhances the significance of intermolecular attractive forces, which facilitates the gas-to-liquid phase transition.

Step-by-step solution

Definition of Liquefaction Process

Liquefaction process is a technique used to convert a gas into a liquid state by reducing its temperature and increasing its pressure. This process is essential for the storage and transport of gases such as natural gas, helium, and nitrogen.

Compressing Gases to High Pressures

The main reason for compressing gases to very high pressures in the liquefaction process is to increase the density of the gas, bringing the gas molecules closer together. Compressing the gas reduces the volume it occupies, and it is easier and more economical to store and transport a gas in a liquid state than in a gaseous state.

Boyle's Law and the Liquefaction Process

According to Boyle's Law, the pressure of a gas is inversely proportional to its volume at a constant temperature (P_1 V_1 = P_2 V_2). Thus, when the pressure of a gas is increased, its volume decreases. This change helps to facilitate the conversion of the gas into a liquid state.

Effect on Intermolecular Forces

Another important factor is that by increasing the pressure, intermolecular forces between gas molecules have more impact. When gas molecules are brought closer together, attractive forces between them become more significant, making it easier for the gas to transition into a liquid state.

Critical Point

The critical point is defined as the temperature and pressure above which a substance cannot exist in the gas and liquid state simultaneously. For the liquefaction process, it is necessary to maintain a temperature and pressure below the critical point of the gas, so that the gas can actually transform into a liquid state. In conclusion, gases are compressed to very high pressures in the liquefaction process mainly to increase their density, make them easier to store and transport, and to bring gas molecules closer together, increasing the significance of intermolecular attractive forces and facilitating the gas-to-liquid phase transition.