Calculate the Temperature and Pressure of a melting point

In summary, the problem statement provides the equation for the derivative of pressure with respect to temperature at constant entropy, along with all necessary parameters. The equation for the slope of the fusion curve is also given, with the knowledge that it passes through 0 C at 1 atm. When graphing pressure vs. temperature for the solid phase, it is assumed that the partial derivative of pressure with respect to temperature remains constant and the specific volume of ice remains constant.
  • #1
romanski007
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1
Homework Statement
Ice is initially at -3C and 1atm. The pressure is increased adiabaticallu until the ice reaches the melting point. At waht temperature and pressure is this melting point? (Hint: At what point does a line whose slope is (dP/dT)_s cut a line whose slope is that of the fusion curve, -1.35 x 10^7 Pa / K?)
Relevant Equations
(dP/dT)_s = c_p / (Tv \beta) , c_p = 2.01 kJ / kg K, v = 1.09 x 10^-3 m^3 / kg and beta = 1.58 x 10^-4 / K
Adiabatic increase in pressure implies Tds=0, can someone tell me how to proceed?
 
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  • #2
The problem statement gives you the equation for the derivative of P with respect to T at constant s, together with all the parameters you need to calculate it. You also have the equation for the slope of the fusion curve, and you know that, at 1 atm, the fusion curve passes through 0 C.
 
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  • #3
Chestermiller said:
The problem statement gives you the equation for the derivative of P with respect to T at constant s, together with all the parameters you need to calculate it. You also have the equation for the slope of the fusion curve, and you know that, at 1 atm, the fusion curve passes through 0 C.
Chestermiller said:
The problem statement gives you the equation for the derivative of P with respect to T at constant s, together with all the parameters you need to calculate it. You also have the equation for the slope of the fusion curve, and you know that, at 1 atm, the fusion curve passes through 0 C.

Should I assume that the partial derivative of P wrt T remains constant throughout the process or that the specific volume of ice remains constant to work out the graph of P vs T for solid phase? Thanks.
 
  • #4
romanski007 said:
Should I assume that the partial derivative of P wrt T remains constant throughout the process or that the specific volume of ice remains constant to work out the graph of P vs T for solid phase? Thanks.
Assume constant partial derivative.
 
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1. What is the purpose of calculating the temperature and pressure of a melting point?

The purpose of calculating the temperature and pressure of a melting point is to determine the conditions under which a substance will change from a solid to a liquid state. This information is important in various industries, such as materials science, chemistry, and manufacturing, as it can help predict and control the behavior of substances.

2. What factors affect the temperature and pressure of a melting point?

The temperature and pressure of a melting point can be affected by several factors, including the chemical composition of the substance, the strength of intermolecular forces, and the presence of impurities. External factors such as atmospheric pressure and the rate of heating or cooling can also play a role.

3. How is the temperature and pressure of a melting point experimentally determined?

The temperature and pressure of a melting point can be experimentally determined using techniques such as differential scanning calorimetry, which measures the heat flow of a substance as it is heated or cooled. Other methods include using a melting point apparatus, which observes the point at which a solid begins to melt, and pressure-temperature phase diagrams, which show the relationship between temperature, pressure, and the states of a substance.

4. Can the temperature and pressure of a melting point change?

Yes, the temperature and pressure of a melting point can change depending on the conditions under which the substance is heated or cooled. For example, increasing the pressure can raise the melting point of a substance, while adding impurities can lower the melting point. Additionally, changes in atmospheric pressure and temperature can also affect the melting point of a substance.

5. How is the temperature and pressure of a melting point used in practical applications?

The temperature and pressure of a melting point have various practical applications, such as in the production and quality control of materials, the design of industrial processes, and the development of new products. For example, knowing the melting point of a substance can help engineers determine the best conditions for casting or molding it into a desired shape, while also ensuring its structural integrity and performance.

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