a. A sample of water vapor in an enclosed cylinder has an initial pressure of 500 Pa at an initial temperature of . A piston squeezes the sample smaller and smaller, without limit. Describe what happens to the water as the squeezing progresses. b. Repeat part a if the initial temperature is warmer
As the piston squeezes the sample the pressure increases.
The initial pressure is less than .
In chapter 15 we defined 1atm as 101,300 Pa.
So $500\displaystyle \cdot=0.005 atm.
$ We now refer to the phase diagram in Figure 16.4.
In order to determine what will happen to a water vapor under these circumstances we need to take a look at a phase diagram for water (find it in the chapter).
The pressure of is a bit less than 0.005 atm and the temperature of is on the left side of the first vertical dashed line (at ). Therefore, the initial phase of water is gas, just as the problem tells us.