Chemistry Regents Practice Test

An ideal gas is defined as a hypothetical gas that perfectly follows the ideal gas law, which states that the pressure, volume, and temperature of a gas are related in a way described by the equation PV = nRT. In this framework, an ideal gas is thought to have molecules that do not interact with each other and occupy no volume. This means that the behavior of an ideal gas can be precisely predicted using the ideal gas law under various conditions of temperature and pressure.

In real-life scenarios, no gas behaves perfectly as described by the ideal gas law due to factors like intermolecular forces and the finite volume of gas molecules, which become significant at high pressures and low temperatures. However, many gases behave similarly to ideal gases under standard conditions, making the concept useful for calculations and understanding gas behavior.

Other options do not accurately represent the concept of an ideal gas. A gas that has no mass is not possible since all matter has mass. The ability of a gas to be compressed does not specifically define an ideal gas, as all gases can be compressed to varying extents. A gas that reacts vigorously with other elements does not relate to the ideal gas behavior and instead pertains to chemical reactivity, which is independent of the ideal gas definition.