# I Question about vapor pressure...

1. Jul 3, 2016

### matt schwartz

A QUESTION. Suppose I enclose water within a large noncombustible substance, say a block of concrete. The water is completely enclosed and sealed = no way for it to escape. Now, I heat the block. I get it very hot. At any temperature I can raise it to, will it still be just water at the ambient temperature? Suppose I could raise it to some enormous temperature, 10K, would it still be just...liquid water? If there was some extra room for the water to vaporize, would it then create steam at that temperature? I assume so! Is there any temperature I could raise it to so it would NOT be liquid water? What would that be?

2. Jul 4, 2016

### parshyaa

The water will remain a liquid for longer time....but as the temp. is raised it starts converting into a gas,a highly pressurised gas. If the temp. is raised even more then the block holding it would simply break and make way for the escaping gas, as gases tend to love free space.

3. Jul 5, 2016

### Staff: Mentor

What makes you think it will be at ambient temperature (20 C)?

If the block is rigid and non-porous, as the water becomes heated, it will remain a single phase, but its pressure will get higher.
At that temperature, it would no longer be considered liquid water (even though it stayed a single phase all the way up to that temperature). Once the temperature exceeded the critical temperature of water, the contents of the block would be considered a "gas."
If there was head space to begin with, even at 20 C, there would be water vapor in the head space. Depending on the original proportions of liquid water and water vapor in the block, the water could expand to eliminate the vapor space, or the vapor space could continue to persist even up to temperatures approaching the critical temperature.
If the temperature is above the critical temperature, no matter how high you increase the pressure, you will not be able to cause the water to condense.