Question

21. Why does a beaker of 40.0°C wat At what pressure does the boiling begin? Would food cook any faster in such a beaker? er placed in a vacuum chamber start to boid as the chamber is evacuated (air is pumped out of the chamber)?

Answer 1

We all know that if you heat water up, it will boil. The temperature at which the water boils depends on the atmospheric pressure.

Water actually boils at a lower temperature if the pressure around it is lowered. This is why, if you go to a high altitude location, where the atmospheric pressure is lower, water will boil at slightly less than 100℃.

In a vacuum chamber, the pressure can be extremely low. So low, in fact, that the water can actually boil at room temperature.

Si, if you put some water in a high-vacuum chamber, you will see it boil. Then, with all that water vapour around, it won't be a high vacuum anymore.

Here is a table showing the variation of boiling point of water with pressure.

But, food cannot be copied in such vacuum chambers. As the water starts to boil in the chamber, suppose we add some vegetables to the water and vacuum pressured steam is supplied to this chamber. But the water vapor in this case would be cold, so it wouldn't cook anything.