How does atmospheric pressure affect the boiling point of a liquid

How does atmospheric pressure affect boiling points? Chemistry Gases Atmospheric Pressure. Jun 4, Related questions How does atmospheric pressure affect evaporation?

How do you calculate atmospheric pressure at an altitude? Why is air pressure greatest at the Earth's surface? What causes hydrostatic pressure in blood vessels? How is hydrostatic pressure created? The higher the air pressure, the harder it is for the liquid to evaporate. Therefore, the boiling point of a solvent or liquid is affected by the atmospheric pressure and boiling point is raised.

You often hear that the air is thinner on a mountain and some people get nose bleeds, dizziness, and nausea at high altitudes because there is less oxygen. Therefore, the atmospheric pressure you experience will be lower. When the atmospheric pressure is reduced, the water molecules on the surface of the water need less energy to bounce upwards to escape into the atmosphere.

I found your info and thought it was very well done and easy to understand. I teach 7th graders and they have a hard time with these concepts.

The boiling point of a liquid depends on temperature, atmospheric pressure, and the vapor pressure of the liquid. When the atmospheric pressure is equal to the vapor pressure of the liquid, boiling will begin. The bubbles in a boiling liquid are made up of molecules of the liquid which have gained enough energy to change to the gaseous phase. When boiling occurs, the more energetic molecules change to a gas, spread out, and form bubbles.

These rise to the surface and enter the atmosphere. It requires energy to change from a liquid to a gas see enthalpy of vaporization. In addition, gas molecules leaving the liquid remove thermal energy from the liquid.

Therefore the temperature of the liquid remains constant during boiling. A graph of temperature vs. As long as there is liquid the temperature will remain constant. The pressure of gas above a liquid affects the boiling point. In an open system this is called atmospheric pressure.

The greater the pressure, the more energy required for liquids to boil, and the higher the boiling point. In an open system this can be visualized as air molecules colliding with the surface of the liquid and creating pressure. This pressure is transmitted throughout the liquid and makes it more difficult for bubbles to form and for boiling to take place. If the pressure is reduced, the liquid requires less energy to change to a gaseous phase, and boiling occurs at a lower temperature.