究竟Specific latent heat of fusion同s.l.h of vaporization點樣用?

Specific latent heat of fusion is means how much energy of a kg water to melt required (change its state)
Specific latent heat of vaporization is means how much energy of a kg water to boil required (change its state)
if we have to calculate the energy required to melt &boil a kg of water ,we should use this two equation together and also(mc=delta T)
e.g.
1)how much energy are required to melt 0.1kg of ice?
E=mlf
E=0.1*3.34*10^5
E=33400J
2)how much energy are required to heat 0.1kg of wate from 0℃ to 100℃?
mc=delta T

E=0.1*(100-0)*4200
E=42000J
*delta T is the tempurature difference
*4200 is the Specific latent heat of water,different substance have different
Specific latent heat

3)how much energy are required to boil 0.1kg of water from 100℃?
E=mlf
E=0.1*2.26*10^6
E=226000J

So,total energy required to change 0℃ ice to 100℃ is:
334000+42000+226000
=564200J

Hope those can help you!

2007-06-18 16:25:23 補充：
So,total energy required to change 0℃ ice to 100℃"steam" is:334000+42000+226000=564200J

如果要計一樣物質狀態轉換所需既能量
就要計潛熱

Specific latent heat of fusion 係溶解比潛熱
用黎計固體變液體所需能量

Specific latent heat of vaporization 係氣化比潛熱
用黎計液體變氣體所需能量


如果件object狀態轉完又轉, 就要用2個

例如: 冰由0加熱到水蒸氣100度所需既能量

= 溶解潛熱 + 能量加熱0度水至100度水 + 氣化潛熱


明唔明???

Specific latent heat of fusion is used to described the energy required to change a substance from liquid to solid or solid to liquid.

Specific latent heat of vaporization is used to described the energy required to change a substance from gas to liquid or liquid to gas.

For example, when you describe the energy water needs to change to ice, you should use Specific latent heat of fusion . But when you describe the energy water needs to change to steam, you should use Specific latent heat of vapourization .