Final answer:
Using Charles's law, which relates volume and temperature of a gas at constant pressure, the new volume of the gas when temperature decreases from 300K to 250K is calculated to be 1.0 L.
Step-by-step explanation:
The question relates to the behavior of gases under temperature changes, which requires an understanding of Charles's law.
Charles's law states that at constant pressure, the volume of a fixed amount of gas is directly proportional to its temperature measured in Kelvins. We can express this as V₁/T₁ = V₂/T₂, where V₁ and T₁ are the initial volume and temperature, and V₂ and T₂ are the final volume and temperature.
To find the new volume (V₂) when the temperature changes from 300K to 250K, we rearrange the formula as V₂ = V₁ * (T₂/T₁). Plugging in the values: V₂ = 1.2 L * (250K / 300K), which calculates to V₂ = 1.0 L. Therefore, the new volume of the gas at 250K would be 1.0 L.