| R-134a at
its triple point is
held in a rigid vessel.
How many intensive variables can be independently specified? |
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| Read : |
At the triple point,
all three phases exist in equilibrium. |
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This is the unique
aspect of the triple point and this problem. |
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| Diagram: |
A diagram is not
necessary for this problem. |
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| Given: |
Number of chemical
species present: |
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C |
1 |
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Number of phases present
at equilibrium: |
P |
3 |
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| Find: |
oFree = |
??? |
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| Assumptions: |
None. |
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| Equations
/ Data / Solve: |
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Gibbs
Phase Rule : |
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oFree = C - P + 2 |
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oFree = |
0 |
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NO intensive variables can be independently specified at the triple point ! |
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This means that there
is just one triple point and all of the properties of all of the phases are fixed ! |
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The triple
point is unique. |
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| Verify: |
No assumptions were made
in the solution of this problem. |
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| Answers : |
oFree |
0 |
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