Question 33 TK02 - Tank Vessel Assistant - Liquefied Gas

The Correct Answer is C **Why option C ("A substance that at normal temperature and pressure would be a gas.") is correct:** A liquefied gas is a substance that exists as a gas under standard conditions (normal temperature and pressure, or NTP/STP) but has been converted into a liquid state, typically by applying high pressure or significantly cooling it, or both. The defining characteristic is that the substance's normal state at ambient conditions is gaseous. For example, Propane or Oxygen are gases that are stored and transported in their liquefied form. **Why the other options are incorrect:** * **A) A liquid that requires to be heated above normal ambient temperature to make it form a gas.** This describes a conventional liquid with a boiling point above ambient temperature, such as water or oil. A liquefied gas's normal boiling point is actually *below* ambient temperature. * **B) A liquid that needs to be stored at absolute zero to prevent it from becoming gaseous.** Absolute zero (0 Kelvin) is the theoretical lowest possible temperature. While many gases are liquefied via extreme cooling (like liquid helium), storing them at absolute zero is impractical and unnecessary for most common liquefied gases. This option describes an extreme scenario, not the general description of a liquefied gas. * **D) A gas that is mixed with another substance that causes it to liquefy.** Liquefaction is a physical process achieved by changing the thermodynamic conditions (pressure and temperature) of the gas itself, not by chemically mixing it with another substance to force a phase change. While mixtures of liquefied gases exist (like LPG), the initial liquefaction of the component gases is done without the aid of a third-party liquid catalyst.