259,000 Joules
To calculate the heat energy needed to change 100 grams of liquid water at 75°C to vapor at 225°C, we will do this in steps;
Mass of water = 100 g
Heat capacity of water = 4.184J/g °C
Temperature change (75°C to 100°C) = 25°C
Using the formula to get Quantity of heat;
Q = mcΔT
  = 100 g × 4.184 J/g °C × 25°C
 = 10,460 joules
Mass of water = 100 g
Heat of vaporization = 2,256 J/g
Heat required to change water to vapor without a change in temperature is given by;
Q = m × Lv
  = 100 × 2,256 J/g
 = 225,600 Joules
Mass of vapor = 100 g
Specific heat of gas = 1.84 J/g °C
Change in temperature (100°C to 225°C) = 125°C
Therefore;
Q = mcΔT
 = 100 g × 1.84 J/g °C × 125°C
 = 23,000 joules
Total energy = 10,460 J + 225,600 J + Â 23,000 J
           = 259,060 J
           = 259,000 J(approx)
Therefore, heat energy required is 259,000 Joules