An ideal monatomic gas initially at 298 K and 1 atm pressure is

Question

expanded from a volume of 1 liter to 2 liters. Consider separately
isobaric, isothermal and adiabatic expansions to accomplish this. In each
case, calculate the following:
a) The final temperature of the gas
b) The amount of work done by the gas in Joules
c) The amount of heat added to the gas in Joules
d) The change in energy of the gas in Joules

I've tried to do this multiple times but I'm really confused about the equations and when to apply them.