Question

a burn on your arm from 100°c steam is more severe than a burn from 100°c water because
multiple choice
100°c steam contains more energy (540 cal/g) than 100°c water.
water is a better conductor of heat.
steam is a gas, which has spread - out molecules and less energy

Explanation:

When \(100^{\circ}C\) steam comes into contact with the skin, it first condenses to \(100^{\circ}C\) water. The latent heat of vaporization (for water, \(540\) cal/g) is released during this phase - change process. So, \(100^{\circ}C\) steam has more energy (due to the latent heat of vaporization) than \(100^{\circ}C\) water. Water being a better conductor of heat is not the reason for the more severe burn (as steam is the one causing more damage here). Also, steam (as a gas) having spread - out molecules and less energy is incorrect because during condensation, the energy is released.

Answer:

\(100^{\circ}C\) steam contains more energy (\(540\) cal/g) than \(100^{\circ}C\) water.