Water vapor burn

[Brandon Yu]

Why does a burn from water vapor at 120 degrees hurt much more than a burn from boiling water at 120 degrees?

[Emma Kelly 3L]

The graph we were given shows that there is much more energy in water vapor at 100 degrees than liquid water at 100 degrees (because the phase change requires a lot of energy), so that's why a vapor burn would be more severe.

[Jocelyn Chin 1K]

Hi! Water vapor holds a lot of energy becuase it takes a lot of energy (40.7 kJ/mol) to turn liquid water into a vapor. However, it doesn't take as much energy to boil water. The water vapor is at a really high temperature, and when water vapor touches your skin, it condenses into liquid. When that water vapor condenses, all the heat (the 40.7 kJ/mol) used to vaporize the liquid water is going to be released on your skin, which is why the burn from water vapor is much more severe.

[Alyssa Cua 2J]

Hi! Water vapor holds a lot of energy becuase it takes a lot of energy (40.7 kJ/mol) to turn liquid water into a vapor. However, it doesn't take as much energy to boil water. The water vapor is at a really high temperature, and when water vapor touches your skin, it condenses into liquid. When that water vapor condenses, all the heat (the 40.7 kJ/mol) used to vaporize the liquid water is going to be released on your skin, which is why the burn from water vapor is much more severe.

Super clear explanation. Thank you, this helped a lot!

[Joelle Tran 1K]

Steam contains even more energy than water that has been boiled due to its vaporization energy, which gives it an additional 22.5 E5 J/kg. When the steam touches your skin, it experiences a phase change from gas to liquid and transfers its energy into your skin. Boiling water does not experience a phase change like the steam so it gives off less painful energy.