What are the Properties of Refrigerant 134a in a Piston-Cylinder Device?

In summary, a piston-cylinder device with 0.85 kg of refrigerant 134a at -10 degrees celsius and a free-moving piston with a mass of 12 kg and diameter of 25 cm, is subjected to heat transfer until the temperature reaches 15 degrees celsius. The final pressure is determined to be 90.4 kPa, and the change in volume and enthalpy of the refrigerant 134a need to be calculated using the tables and specific volume values at both initial (-10 degrees celsius) and final (15 degrees celsius) states. The specific volume at initial state is obtained using the values of -10 degrees celsius and 90.4 kPa, while the specific volume
  • #1
Suitengu
46
0
A piston-cylinder device contains 0.85 kg of refrigerant 134a at -10 degrees celsius. The piston that is free to move has a mass of 12 kg and diameter of 25 cm. The local atmospheric pressure 88 kPa. Now, heat is transferred to refrigerant 134a until the temperature is 15 degrees celsius. Determine
(a)the final pressure
(b)the change in the volume of the cylinder and
(c)the change in enthalpy of the refrigerant 134a


I did part a and got it to be 90.4 kPa as P1 = P2, a value of which I am about 95% sure being correct.

As for part b, I deduce that I should use the tables in some method but I'm stumped with how to proceed. I tried to calculate the V of initial and final to get delta V but I am stuck at this equation

V = mv

So I figure i may have to use -10 degrees celsius and 90.4 kPa to get the specific volume at the initial state and 90.4 kPa and 15 degrees celsius to get specific volume at the final state.

Plz pt me in the right direction if you can.
 
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  • #2
c'mon guys its been over two days an no help...oh man
 

Related to What are the Properties of Refrigerant 134a in a Piston-Cylinder Device?

What is a pure substance?

A pure substance is a material that has a fixed and definite chemical composition and physical properties. It cannot be separated into simpler components by physical means.

What are the two types of pure substances?

The two types of pure substances are elements and compounds. Elements are made up of only one type of atom, while compounds are made up of two or more different types of atoms chemically bonded together.

What are the physical properties of pure substances?

The physical properties of pure substances include melting point, boiling point, density, solubility, and specific heat capacity. These properties are dependent on the chemical composition and arrangement of particles in the substance.

How do pure substances differ from mixtures?

Pure substances have a fixed and definite composition, while mixtures can vary in composition. Pure substances also have consistent physical and chemical properties, whereas mixtures can have varying properties depending on the proportion of each component present.

Why are pure substances important in scientific research?

Pure substances allow for controlled experiments, as their consistent properties make it easier to isolate and study specific substances. They also serve as the basis for understanding and predicting the properties and behavior of more complex materials.

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