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Why steam burns are worse explained

Posted: Thu Jan 11, 2018 12:24 am
by Beza Ayalew 1I
Hey, could someone please clarify why steam burns are worse than others? I know part of the explanation is that it takes around 40kJ to break liquid water bonds into water vapor, so is the reasoning just that the steam is holding in all that excess energy which causes more severe burns or not?

Re: Why steam burns are worse explained

Posted: Thu Jan 11, 2018 1:59 am
by Kyle Sheu 1C
In essence, yes.

When the steam hits your skin, there is a temperature difference, and heat passes from the steam to your skin as the water vapor condenses. Because there is so much more energy in steam than 100 degree water b/c of the energy "invested" during the phase change, the burn is more severe.

Re: Why steam burns are worse explained

Posted: Thu Jan 11, 2018 11:29 am
by Sue Xu 2K
The steam and water all tend to cool down when it get exposed to a cooler surface like the skin. But it releases extra energy to convert steam to water first, and then the extra energy, or extra heat would burns the skin worse.

Re: Why steam burns are worse explained

Posted: Thu Jan 11, 2018 11:34 am
by Harrison Wang 1H
When steam hits your hand, it first condenses, and because ∆H for the vaporization of water is extremely high, a lot of heat is released upon contact with your body. When water hits your hand, it does not require this phase change, and the heat transferred to your body is therefore much less.

Re: Why steam burns are worse explained

Posted: Thu Jan 11, 2018 1:08 pm
by Erica Nagase 1H
After 100 degrees, vaporization is complete so the temperature of steam can be much greater than 100 deg (think of the phase change diagram from lecture). Because the temperature is higher, there is a greater change in enthalpy.

Re: Why steam burns are worse explained

Posted: Wed Jan 17, 2018 12:53 am
by Beza Ayalew 1I
ok thanks guys, so what I got from that was the major concept is that because steam requires a phase change when in contact with the skin but liquid water doesn't, the energy needed to complete the phase change results in more burns.