Steam graph

[305086803]

Could someone explain in depth the steam graph that Dr. Lavelle used in class to explain why steam causes sever burns?

[chemboi]

While another poster may want to break it down super in depth, I think throughout interpretation of explanations you should keep in mind the differences between the heat energy of the water and its temperature. For steam, increasing temperature requires imparting more heat.

[Brian_Ho_2B]

Steam causes severe burns at 100C vs water at 100C because not only was there a lot of heat to supply H2O to that temperature, but there was a LOT more heat supplied to get it from a liquid to a gas phase. That combined amount of heat is much more heat that just water at 100C. When steam touches skin, it releases all the heat it took to get to a gas phase and it releases the heat from it being a temperature of a 100 degrees celcius

[Brian Tangsombatvisit 1C]

When water in liquid form at 100 C comes into contact with skin, energy is transferred from the water to your skin since it is at a higher temperature. However, with water in vapor form at 100 C, when it comes into contact with your skin, it condenses, transforming from a vapor to a liquid, releasing additional energy (the water undergoes a phase change). The additional energy, Hvap/Hcondensation, is very large and is the reason why steam would burn you more.

[romina_4C]

The graph that he showed was the heating curve for water. Other people have already explained the steam portion, so I'll talk about the graph itself. The y-axis is temperature and the x-axis is heat absorbed. When the heat added is increasing and the graph is increasing (line has a slope), then the temperature of the substance is increasing but there is no phase change. The heat added is going into increasing the temperature of the substance. When the heat added is increasing and the temperature of the substance stays the same, then the substance is going through a phase change. The heat added is going into changing the state of the substance.

[305086803]

Thanks so much everyone for the help!