1. The problem statement, all variables and given/known data(adsbygoogle = window.adsbygoogle || []).push({});

For a certain experiment, R-410a vapor is contained in a sealed glass tube at 20°C. It is

desired to know the pressure at this condition, but there is no means of measuring it, since

the tube is sealed. However, if the tube is cooled to −20°C small droplets of liquid are

observed on the glass walls. What is the initial pressure?

2. Relevant equations

Thermodynamic tables

ideal gas equation?

3. The attempt at a solution

I set up both states:

State 2: T = -20 (saturated)

State 1: T = 20, v1=v2=0.0648 P = ? (superheated)

I just don't understand how we can figure it out from just the temps. I just cant wrap my mind around the thermodynamic tables.

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# Homework Help: Thermodynamics - Find initial pressure (given Temperatures)

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