Final answer:
The phase of a substance at 250°C and 1.00 atm depends on its specific melting and boiling points which are determined by intermolecular forces and particle energy. Therefore, the correct answer is D) Depends on the substance.
Step-by-step explanation:
The phase of a substance at 250°C and 1.00 atm is D) Depends on the substance. Different substances have different melting and boiling points, which means their phase changes occur at different temperatures and pressures. For example, water at 1 atm boils at 100°C and is in a gaseous state at 250°C, whereas iron has a melting point well above 250°C and would still be a solid at this temperature and pressure.
When considering a substance with relatively strong intermolecular forces and a high melting point that is not easily compressed, it will most likely be in the solid state at lower temperatures. As the temperature increases, such a substance might become a liquid or a gas, depending on whether it has reached its melting or boiling points, respectively.
In summary, the energy of the particles and the balance of intermolecular forces are crucial in determining the state of matter. As temperature increases, a substance can transition from solid to liquid to gas, provided it does not decompose in the process due to bonds that are too weak to withstand the high temperature.