To liquify a fixed amount of gas, one may 1. increase the temperature while decreasing the pressure. 2. increase the volume while increasing the pressure. 3. decrease the temperature while decrease

The complete question is:

To liquify a fixed amount of gas, one may 1. increase the temperature while decreasing the pressure. 2. increase the volume while increasing the pressure. 3. decrease the temperature while decreasing the pressure. 4. decrease the temperature while increasing the pressure. 5. decrease the volume while decreasing the pressure.

4. decrease the temperature while increasing the pressure

Explanation:

The thermodynamics explains the sate of a substance (generally a gas or a liquid), which is its characteristics: temperature, pressure, volume, enthalpy, etc. When they changed, the state changes. Some of these changes may induce a physical change.

A gas has distant and agitated molecules, thus, the pressure is low and the temperature is higher, and a liquid has more close and less agitated molecules, so with higher pressure and low temperature.

Thus, to liquefy a fixed amount of has one may decrease the temperature while increasing the pressure.