Final answer:
The volume of carbon dioxide gas will be less than 25 L after cooling down from 12000 °C to 25 °C due to Charles's Law, which indicates that the gas volume decreases with temperature when pressure is constant.
Step-by-step explanation:
When marble decomposes at 12000 °C to form carbon dioxide gas (CO₂) and lime, the 25 L of CO₂ collected at that high temperature will have a different volume when it cools down to 25 °C. According to Charles's Law, which states that if the pressure on a sample of a dry gas is kept constant, the volume of the gas is directly proportional to its temperature (measured in Kelvins), the volume of the gas will decrease when the temperature is reduced.
The formula to apply Charles's Law is V1/T1 = V2/T2, where V1 is the initial volume of the gas, T1 is the initial temperature, V2 is the final volume after the temperature change, and T2 is the final temperature.
Therefore, the correct answer is that after cooling the gas from 12000 °C to 25 °C, the volume of the CO₂ will be less than 25 L. This is because when the temperature decreases while the pressure remains constant, the volume of a gas also decreases. So the appropriate choice is: c. Less than 25 L.