Question

Steam causes more severe burns than boiling water at the same temperature.

Answer 1

Hint: In order to solve this question, firstly we will understand the concept of latent heat of vaporization. Then we will compare both the effects of steam and boiling water with ${100^ \circ }c$ to get the required result.

Complete step-by-step solution -

As we know that in comparison to water, steam contains more heat in the form of latent heat of vaporization. Latent vaporisation heat is a substance's physical property.
It is defined as the heat required to change one mole of liquid at its boiling point under standard atmospheric pressure. It is expressed as kg per mol or KJ/Kg.When energy is supplied to a substance in liquid form, it changes its phase from liquid to vapor; the energy absorbed in this cycle is called vaporisation heat.
Steam has more energy than boiling water at the same temperature i.e. 100 degrees celsius. It possesses the additional latent heat of vaporization. So, when steam falls on the skin it condenses and produces water $22.5 \times 105J{\text{ per }}kg$ which produces more heat than boiling water at the same temperature.
Also we know that the heat of vaporization is so large, steam carries a great deal of thermal energy that is released when it condenses, making water an excellent working fluid for heat engines.
Therefore, we conclude that when steam falls on skin and condenses to produce water it gives out$22.5 \times 105J{\text{ per }}kg$ more heat than boiling water at the same temperature. So, it implies that Steam causes more severe burns than boiling water at the same temperature.

Note- While solving this question, we must know the concept of latent heat of vaporization. Also one must know that the heat of vaporization at 100 degrees celsius is about 2230 joules (533 calories) and the SI unit of energy is joule.