Answered

Why would contact with steam at 100 C produce a more severe burn than contact with liquid water at the same temperature?

Answer :

 In order to form steam, water is needed to boil. In order to boil water, it has to be drastically heated to a much higher temperature. Once boiled, the water will begin to vaporize into steam. As compared to the original liquid phase of water, steam is a much more heated gas version of water that also has much stronger intermolecular forces. 

Hey there!

Why would contact with steam at 100 C produce a more severe burn than contact with liquid water at the same temperature?

This is because the steam at 100 °C is formed by absorbing more heat energy during the change of state from water to vapour which we call as the latent heat of vapourization or boiling.