中三問題解說

水的比熱容量=4200焦耳每千克每度
水的汽化比潛熱=2.26x10^6焦耳每千克

0度的水變為100度的水所需的能量
=mc△T =0.1x4200x(100-0)=42000焦耳

100度的水變為100度的水蒸氣所需的能量
=mlv =0.1x(2.26x10^6)=2.26x10^5焦耳

總能量 =42000+2.26x10^5
=42000+226000
=268000焦耳
=2.68x10^5 焦耳

p.s. 水的汽化比潛熱認可值為2.26x10^6 lv=汽化比潛熱 lf=熔解比潛熱
可以寫成e=mc△T+mlv

It involves two sections

One is to change the water from ice (0 `C) to liquid state.
This energy is 2250000J (given for you)

The other section is to change from liquid state to vapour (100`C) state.
You use the equation: Q = m c ΔT
Q is the energy ( J)
m is the mass of water (kg) therefore, 1000g = 1kg
ΔT is the change of temperature = 100 in this case
c is the specific heat capacity = 4200

So, you have Q = 1 x 4200 x 100

then you add this energy to 2250000 to get the total energy/ answer.

Hope i can help you! =]