PPT Slide
- In open containers, the atmosphere bears down on the liquid surface.
- As temperature increases, when the E k of the molecules is great enough for bubbles of vapor to form in the interior, the liquid boils.
- Thus, the boiling point is the temperature at which the vapor pressure equals the external pressure, i.e., one atmosphere.
- Once boiling begins, the temperature remains constant until the liquid phase has all vaporized or heating is stopped.
- At high elevations, a lower pressure is exerted on the liquid, so molecules in the interior need less kinetic energy to form bubbles.
- Water boils at 100ƒC at 760 torr (sea level), at 94ƒC at 610 torr (Denver, CO), and at about 72ƒC at 270 torr (top of Mt. Everest).