The molar heat of vaporization for methane, ch4, is 8.53 kj/mol. how much energy is absorbed when 54.8 g of methane vaporizes at its boiling point?
use q = n triangle h.
6.42 kj
29.1 kj
137 kj
467 kj

The answer is the second option 29.1 kJ. We know this because you take the mass so 54.8g divided by the molar mass of methane this will give you the moles which is the n value.Remember that delta mean change and in this case it will be the 8.53kJ/mol. The only thing you need to do in order to reach the 29.1 KJ is multiply the moles you find by 8.53. Hope this helps a lot