Final answer:
The boiling point is where a substance changes from liquid to gas, typically with the highest kinetic energy, and the freezing point is the opposite transition, with the lowest kinetic energy. Water's boiling point is 100°C at 1.00 atm, and density varies with phase. More data is needed to confirm if the substance is water.
Step-by-step explanation:
Understanding the boiling point and freezing point is essential in Chemistry. The boiling point is defined as the temperature at which a substance changes from a liquid to a gas and vice versa for condensation; the boiling point of water is 100°C at 1.00 atm. Kinetic energy is the highest at the boiling point because the molecules have the most movement and the lowest at the freezing point where movement is greatly reduced. The freezing point is the temperature at which a substance changes from a liquid to a solid and vice versa for melting. Whether the substance is water can typically be inferred from its melting and boiling points; however, additional information is needed to confirm. The density is highest in the solid phase and lowest in the gaseous phase. Lines A, C, and E in a phase diagram typically represent the boundaries where phases coexist, and lines B and D often signify transitions like boiling or melting where temperature remains constant despite the intake or release of heat.