What is the 'lightest halogen around'?

Iwll give extra points to who gets this for ! what type of reaction is this? ?

How much heat is released upon converting one mole of steam (18.0 g) from 100.0 ∘c to water at 25.0 ∘c? show work and constants, trying to figure out how it works. only given the heat capacity for steam and water so try to only use that

How many moles of gas are present if p=11 atm, v=12l, t=185k?