Question

The melting temperature (or freezing temperature) is the temperature at which, under a specified pressure, the liquid and solid phases of a substance"

A) Have equal enthalpies
B) Achieve maximum entropy
C) Coexist in equilibrium
D) Reach a critical point

Answer 1

The melting temperature, or freezing temperature, is where the solid and liquid phases of a substance coexist in equilibrium. This is a fixed property for a substance, demonstrated when water melts or freezes at 0°C under normal atmospheric pressure.

Step-by-step explanation:

The melting temperature (or freezing temperature) is the temperature at which, under a specified pressure, the liquid and solid phases of a substance coexist in equilibrium. This temperature is a fixed point for each substance and is a physical property that characterizes the substance. For example, the melting and freezing points of water are 0°C and 1.00 atm pressure. At this point, the molecules of ice acquire enough energy to become a liquid, or conversely, the water molecules lose energy to become a solid. During this phase transition, no temperature change occurs even though heat energy is transferred because the substance is at equilibrium. Both the processes of melting and freezing occur at equal rates when the substance is perfectly insulated, resulting in no net change in the amounts of solid and liquid.

Answer 2

The melting temperature (or freezing temperature) is the point at which the solid and liquid phases of a substance coexist in equilibrium, such as water at 0°C.

The correct answer is C.

Step-by-step explanation:

The melting temperature (or freezing temperature) is the temperature at which, under a specified pressure, the solid and liquid phases of a substance coexist in equilibrium. This means that, at the melting point, the processes of melting and freezing occur at equal rates, and the amount of substance in the solid phase and liquid phase remains constant. As an example, for water, the equilibrium between ice (solid phase) and liquid water occurs at 0°C, which is both its melting and freezing point.

It's critical to understand that the term 'melting point' or 'freezing point' depends on the direction of the state change being considered - whether a substance is transitioning from a solid to a liquid (melting), or from a liquid to a solid (freezing).