# Boiling Point #2

Notes for the Boiling Point Article

• Water boils at 100℃ at sea level
• Water boils at 70℃ at the top of Mount Everest
• Kinetic energy makes particles of the liquid vaporise
• Boiling point happens when all the molecules throughout the liquid have enough kinetic energy to vaporise.
• Boiling point is the temperature at which the vapour pressure of a liquid is equal to the external pressure
• Some liquid evaporates even when the liquid is below its boiling point
• When vapour pressure inside the bubble is equal to the external atmospheric pressure, bubbles rise to the surface and burst.
• Temperature at this process is the boiling point of the liquid
• Normal boiling point is the temperature which the vapour pressure of the liquid is equal to the standard pressure
• Boiling point of a liquid changes with external pressure

Question 1: What is the boiling point of water in degrees Celsius and Fahrenheit?

100℃, or 212℉

Question 2: How does the boiling point of water change at altitudes below sea level?

The boiling point only occurs when the vapour pressure inside the bubble is equal to the external atmospheric pressure, so when the altitude that changes the atmospheric pressure changes, then the boiling point of the water would be delayed or early.

Question 3: Does water containing impurities boil at a higher or lower temperature than pure water?

Lower temperature

At the Boiling Point #2 lab, we did almost the same thing as Boiling Point #1 lab: We had a measured amount of water with ice cubes, we boiled it, and the thermometer graphed the data out. But this time, everyone was given a different amount of water, so we saw that different volumes boiled faster or slower. I learned that volume could affect the boiling process, since if the volume is higher, then there would be more liquid to boil and evaporate, which would take more time.

Here’s my group’s graph that the thermometer did for us in Boiling Point #2 Lab.