steam causing more severe burns than water

[905934944]

I am confused about how steam causes more severe burns than water at 100 degrees because how do you get water to 100 degrees without it becoming steam?

[LenaNguyen]

In order to cause a phase change, water must absorb the heat energy used to vaporize the water, which is why the temperature does not change, as it uses the heat to break the bonds to convert itself to steam. Therefore, as opposed to boiling water just at 100 degrees Celsius, which is the temperature that water begins to vaporize at, steam holds a lot more heat energy, and thus would cause more severe burns.

[905934944]

So at the point of phase change 100 degrees is H2O water or steam?

[Minh-Anh Pham 1B]

Phase change isn't a point, but rather an amount of energy that the water has to absorb before it can fully vaporize. When water first comes to a boil, it is at 100C, and it is still water. But later, as the water boils more, it doesn't necessarily increase in temperature but the water molecules absorb more energy while still staying at 100C so that it can vaporize. So technically, at 100C water can be in both states, depending on how much energy was absorbed.

[Ali Nosseir]

Heat and temperature aren't necessarily the same thing. Something can be heated, in this case the water, without the temperature increasing. In order for an endothermic phase change to occur for any substance, the substance's bonds must be broken and to break a substance's bonds requires heat. When water is at 100 C as a liquid, it still is the same temperature of steam at 100 C. However, the amount of heat energy for each phase is different. Liquid water at 100 C still has its hydrogen bonds linking each molecule whereas the steam doesn't possess those bonds.

Therefore, although the temperatures of 100 C water and 100 C steam are the same, their heat energies are different, resulting in steam to cause more severe burns than water.

[Kailyn Kennada 3E]

Hi there, I like to think of the heat the steam maintains from vaporization energy has dormant. Both boiling water and steam contain these dormant heat capacities except steam not only contains the energy for melting but also vaporizing. It is like the dormant energies build on each other, so when the energy is transferred to a person's hand for example, the dormant warmth is much more intense when convert steam to a liquid versus the boiling water. Hope this helped!

[Jasmine Catalan 1H]

From the chart that professor used in lecture he had said that water at 100 degrees keeps getting heat added to it and the straight line means that it’s undergoing a phase change, if I am remembering correctly. So that would mean during that time the heat being added is when the bonds are breaking in the water molecules that then allow it to go to vaporization. Then vaporization will be higher in temperature according to the chart. When someone gets burned with vapor on the skin the skin cools only a small amount of the temperature the vapor was at. Let’s say vapor is at 140 degrees and it meets the skin which is 37 degrees then the skin would only cool that amount and still be at a 100 degrees but now the vaporization turned into water at 100 degrees causing a more severe burn than water. Since water at 100 degree boiling point landing on the skin would cool it about 37 degrees leading to a smaller temperature.

[Oscar Tan 1L]

Remember that temperature and energy are related but different. The liquid water and steam may be at the same temperature, but for water to become a vapor, an immense amount of energy is required. Therefore, steam has much more energy compared to liquid water.