Answer:
45200J
Step-by-step explanation:
Given parameters: 
Heat of vaporization of water = 2260J/g
Mass of steam = 20g 
Temperature = 100°C 
Unknown: 
Energy released during the condensation = ? 
Solution: 
This change is a phase change and there is no change in temperature
 To find the amount of heat released; 
 H = mL 
m is the mass 
L is the latent heat of vaporization
 Insert the parameters and solve;
 H = 20g x 2260J/g 
 H = 45200J