Melting Point and Temperature:9 Facts You Should Know


In this article, let us focus on the facts regarding melting point and temperature you should know.

A transformation of a substance that is in a solid-state into a liquid state is the very well-known process of melting, which is believed to occur generally at a particular point corresponding to the temperature familiarly known to be the melting point and temperature (melting). At this point, there is an equilibrium occurrence of both the solid and liquid forms of the given substance.

We usually determine the range of how much hot or cold a body is with the help of a parameter that is temperature.

The following section deals with the definitions of melting point and temperature.

Melting point and temperature.

  We can witness a transformation of a substance that is in a solid state into a liquid state; this phenomenon is the very well known process of melting, which is believed to occur generally at a particular point corresponding to the temperature familiarly known to be the melting point and temperature associated can also be regarded as the melting temperature. Whereas temperature is nothing but a direction along which the heat energy tends to flow spontaneously.

The next part is concerned with whether the melting point and temperature are the same.

melting point and temperature
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Is its melting point and temperature the same?

As we are already aware that temperature basically represents the energy flowing from a body that is comparatively hotter to another body, i.e., cooler in concern with the first body. In contrast, the melting point is a particular value corresponding to the temperature, which is usually associated with the phenomenon of melting the substance. Therefore, the melting point and temperature are not the same.

 But we can express the similarity or a connection between the melting point and melting temperature here; when we are talking about a substance, we usually choose the parameter melting point that best depicts the precise temperature for melting, whereas the melting point is spread over a range of temperatures for few substances such as polymers.

The upcoming part majorly explains the relationship between melting point and temperature.

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 Relationship between melting point and temperature.

The atoms and molecules in a substance, in accordance with their random motion inside the substance, are said to possess kinetic energy. An average of this possessed kinetic energy can be given by temperature. Here, we can also mention that when the substance’s temperature reaches the melting point, the atoms and molecules are favored to gain more energy.

Thus, there will be an increase in random movements and speed of the constituents, further increasing the system’s entropy due to the conversion into a liquid form from the solid form. This can be the relationship between the melting point and temperature.

Does temperature increase melting point?

At the point of melting along with transforming into a liquid state while it is in solid-state, it is also found that the vapor pressure corresponding to the liquid phase coincides with that of the solid phase giving rise to the equilibrium existence of both the states (i.e., solid and liquid). This is the essence of the phenomenon of melting. If you intend to melt a solid, you need to increase the temperature undoubtedly.

 While you increase the temperature, some substances (pure substances and elements) may undergo melting when you just reach a specific temperature value; that is the melting point. Whereas in order to meet a few mixtures and amorphous solids, you may need to cover a range of values concerning temperature, that is melting temperature.

Is melting point directly proportional to temperature?

We will observe a similar value of vapor pressure corresponding to both liquids as well as the solid phase while they both exist in equilibrium during the process of melting. We are already very well aware that if we increase the temperature associated with the substance, it will melt when we reach a point familiarly known to be the melting point.

Thus, melting point is a fixed characteristic temperature which is a constant that differs from substance to substance but has nothing to do with the surrounding temperature of the substance.

Is temperature constant during a melting point?

When we intend to melt a substance, surely, we are going to fulfill the need for temperature increase through the provision of heat to the substance. The temperature will go on the increase until the melting point; after that, during the phenomenon of melting, the temperature is going to remain constant until and unless the whole substance melts.

The temperature is going to remain throughout the same with no change during both melting point and boiling point. This is to provide energy in the form of heat to overcome the force of attraction that exists in between the particles in the place of temperature increase.

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Why does the temperature remain constant during melting and boiling point?

Let us take a substance and provide heat continuously so that we increase its temperature. At some point, we are going to achieve the melting point; at this point, there occurs a change of state; thus, the heat provided further after reaching this point does not increase its temperature value as it will be fully utilized in order to change the state of the substance. Thus, the temperature remains unvaried throughout the process of melting.

After the whole substance undergoes melting, now again, the heat provided will take part in increasing the temperature as before; this is because if we need to change the state of the substance, we are supposed to overcome the molecular force of attraction that is found to be present in between the constituents of the substance.

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Glass transition temperature and melting point.

Melting point is a particular value corresponding to temperature, which is usually associated with the phenomenon of melting of the substance. Glass transition temperature is the specific value of the temperature when achieved in polymers, inculcates the properties associated with rubber above that temperature. Until it is reached, polymers possess glass-like properties.

Usually, amorphous polymers are substances that show glass transition. Polymers are generally characterized by a thermal transition property. Both the melting point and the glass transition temperature belong to such properties as they, when achieved, trigger the transition of state and properties, respectively.  

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Difference between melting point and glass transition temperature

Below is a table of differences between melting point and glass transition temperature.

Melting temperatureGlass transition temperature
melting point is a particular value corresponding to the temperature, which is usually associated with the phenomenon of melting the substanceThe glass transition temperature is the specific value of the temperature when achieved in polymers, inculcates the properties associated with rubber above that temperature. Until it is reached, polymers possess glass-like properties.  
Melting is categorized under the first-order reactionThe glass transition is categorized under the second-order reaction
Here, we can witness a transformation of a substance that is in a solid-state into a liquid stateHere, A brittle or a glassy state is found in an amorphous or a semi-crystalline polymer which is transformed from a viscous or rubbery state that was existing in those polymers.
Variation of derivatives is not seen in melting.Variations of derivatives can be seen in the glass transition.

Why are the melting point and freezing point the same temperature?

Melting and boiling are the two physical phenomena that take place between the same two states of matter (transition of matter), i.e., melting is the transformation of a substance that is in a solid state into a liquid state. In contrast, freezing transforms in contrast liquid into solid. Both processes occur at the same point associated with the temperature. This is why we observe the same temperature corresponding to both melting point and freezing point.

 Because of cooling, the constituents of the liquid show a tendency for energy loss, further restricting their random motion so that they come into a proper and stable arrangement which is the characteristic property of solids.

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What really happens at a glass transition temperature?

A brittle or a glassy state is found in an amorphous or a semi-crystalline polymer which is transformed from a viscous or rubbery state that was existing in those polymers. This transformation is going to take place once the temperature reaches the point equivalent to the glass transition temperature.

 Generally, hard and rigidity-like glass are the characteristic properties exhibited by polymers, and they are going to show less rigidity above this glass transition temperature. Variation of derivatives can be seen in the glass transition; this is why it is categorized under the second-order transition.

Summary

At the point of melting along with transforming into a liquid state while it is in solid-state, it is also found that the vapor pressure corresponding to the liquid phase coincides with that of the solid phase giving rise to the equilibrium existence of both the states (i.e., solid and liquid). This is the essence of the phenomenon of melting. If you intend to melt a solid, you need to increase the temperature undoubtedly. It is the difference between melting point and temperature.

 

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