Final answer:
The water particles will change phase from liquid to gas when heated from 85°C to 105°C, with the water boiling at 100°C at standard pressure.
Step-by-step explanation:
During the process of heating a sample of water from 85°C to 105°C, the correct description of what the water particles will do is change phase from liquid to gas. At an atmospheric pressure of 1 atm, which is the common pressure at sea level, the boiling point of water is 100°C. As the water is heated to this temperature, the water particles absorb heat energy. The kinetic energy of the water molecules increases until the energy is sufficient to overcome the intermolecular forces that hold the molecules together in the liquid state. Upon reaching the boiling point, the water begins to vaporize, making the transition from liquid to gas. The added heat at this point goes into breaking intermolecular bonds rather than increasing temperature, so the water will remain at a constant temperature of 100°C until it has completely transformed into gas.
If the atmospheric pressure is different, such as being at a higher altitude, the boiling point would be different from 100°C. However, as the pressure is not specified in the question and standard pressure is commonly assumed, it is appropriate to refer to the standard boiling point of water.