Relationship between Latent Heat of Fusion and Temperature

In summary, the conversation discusses the use of the Clausius-Clapeyron Law to calculate the amount of pressure needed to move the melting point of Thorium Dioxide up by 444 degrees kelvin. The purpose is to determine whether it would be feasible to use the substance to line the combustion chamber of a scramjet burning Pentaborane, which burns at high temperatures. The conversation also mentions the issue of using a constant value for Thoria's heat of fusion and the potential solution of lowering the temperature of the reaction.
  • #1
nlieb
16
0
Does latent heat of fusion typically go up or down with temperature? I'm trying to calculate the amount of pressure needed to move the melting point of Thorium Dioxide up by 444 degrees kelvin using the Clausius-Clapeyron Law to see whether it would be feasible to line the combustion chamber of a scramjet burning Pentaborane (which burns at 4107°K, or 3834°C, in pure liquid oxygen, so probably a bit less in air, which has a lot of Nitrogen in it to steal Oxygen from the reaction, but this is probably a reasonably valid approximation given high enough pre-compression of the air since Pentaborane is ridiculously combustible) with the stuff to prevent the whole thing from melting. The idea is that at that temperature, anything other than an oxide is going to be oxidized by oxygen. When I use a constant value for Thoria's heat of fusion, I get a pressure on the order of 1 TPa, obviously too much. Lowering the temperature of the reaction is not a solution because that would lower the pressure generated in the combustion chamber and thus the specific impulse, which would be no fun.
 
Science news on Phys.org
  • #2
Is there a question here?
 

What is the relationship between latent heat of fusion and temperature?

The latent heat of fusion is the amount of energy required to change a substance from a solid to a liquid state, without changing its temperature. The relationship between latent heat of fusion and temperature is that as the temperature increases, the latent heat of fusion decreases. This means that more energy is needed to melt a substance at lower temperatures compared to higher temperatures.

How does the latent heat of fusion affect phase transitions?

The latent heat of fusion plays a crucial role in phase transitions. When a substance is at its melting point, the latent heat of fusion must be supplied in order for the substance to change from a solid to a liquid state. This is because the energy is used to break the bonds between the molecules in the solid, allowing them to move and form a liquid. Similarly, when a liquid reaches its freezing point, the latent heat of fusion is released as the molecules bond together to form a solid.

Is the latent heat of fusion constant for all substances?

No, the latent heat of fusion varies for different substances. This is because it depends on the strength of the intermolecular bonds in the substance. Substances with stronger bonds will require more energy to melt, resulting in a higher latent heat of fusion. On the other hand, substances with weaker bonds will have a lower latent heat of fusion.

How is the latent heat of fusion determined experimentally?

The latent heat of fusion can be determined experimentally by measuring the temperature change of a substance as it undergoes a phase transition. The amount of energy required to change the state of the substance can then be calculated using the equation Q = m * L, where Q is the energy, m is the mass of the substance, and L is the latent heat of fusion. By measuring the mass and temperature change, the latent heat of fusion can be determined.

What factors can affect the latent heat of fusion?

The latent heat of fusion can be affected by various factors such as pressure, impurities in the substance, and the rate of heating or cooling. A change in pressure can alter the strength of intermolecular bonds, resulting in a change in the latent heat of fusion. Impurities can also disrupt the bonding between molecules, affecting the amount of energy needed for a phase transition. Lastly, the rate of heating or cooling can impact the amount of time the substance has to absorb or release energy, which can affect the latent heat of fusion.

Similar threads

Latent heat of fusion for water question
    • Thermodynamics
Replies
8
Views
2K
B What causes the drop of latent heat at lower temperatures in liquid helium?
    • Atomic and Condensed Matter
Replies
2
Views
1K
Exploring the Relationship Between Color and Temperature in Thermal Measurements
    • Thermodynamics
Replies
6
Views
1K
Heat Energy Removed: Latent Heat of Sublimation/Fusion
    • Thermodynamics
Replies
4
Views
2K
Modeling of moist-adiabatic temperature?
    • Thermodynamics
Replies
2
Views
955
Specific latent heat of fusion
    • Introductory Physics Homework Help
Replies
1
Views
2K
The effect of exit pressure and temperature on a turbine
    • Mechanical Engineering
Replies
2
Views
1K
Pressure and temperature of expanding humid air
    • Thermodynamics
Replies
8
Views
3K
Possible error sources in thermal conductivity experiment?
    • Thermodynamics
Replies
16
Views
12K
Automotive Loss of gaseous volume because of fuel combustion
    • Mechanical Engineering
Replies
2
Views
194

Hot Threads

Recent Insights

Back
Top