Final answer:
There is no change in temperature during a phase change because energy is used to break molecular bonds rather than to increase kinetic energy, and the phases where particles are furthest apart are gas and liquid.
Step-by-step explanation:
During a phase change, there is no change in temperature even though energy is absorbed by the system because the energy is used to break the intermolecular bonds, rather than increase the kinetic energy of the particles, which would raise the temperature. In a phase change from solid to liquid or liquid to gas, energy is used to overcome the attractive forces between particles; this process requires energy transfer as latent heat. This latent heat is absorbed without causing a temperature change. During the phase changes of freezing and condensation, energy is released.
In which two phases of matter do atoms and molecules have the most distance between them? The answer is gas and liquid, meaning the correct answer is option (a) 'During phase change, energy is only potential. Gas and liquid.' The two phases where atoms and molecules are furthest apart are the gas phase (where they are very disordered and far apart) and the liquid phase (which has more distance between particles than a solid but less than a gas).