A block of melting ice with mass 0.02 kg is put into a polystyrene cup containing 0.3 kg
of water with initial temperature 20 ''C . After the mixture is stirring well , the ice block melt completely and the final temperature of the water becomes 14 ''C .Which of the following is to find the latent heat of fusion of ice, L ?
0.3x4200x6 =0.02L
0.3x4200x6 =0.02L - 0.02x4200x6
0.3x4200x6 =0.02L+ 0.02x4200x6
0.3x4200x6 =(0.02L+ 0.02x4200)x14
0.3x4200x6 =0.02L+ 0.02x4200x14
Urgent ! Physics , 高人請指教 !
2007-04-25 3:47 am
回答 (2)
2007-04-25 4:03 am
✔ 最佳答案
energy is transferred from the 20 deg 0.3kg water to melt the 0.02kg ice and raise the temperature of the 0 deg 0.02kg water to 14 deg(input) energy offered by the 0.3kg water=(0.3x4200x6)J
(output 1) energy absorbed to melt 0.02kg ice=(0.02L)J
(output 2) energy absorbed to raise the temperature by 14deg=0.02x4200x14
by conservatin of energy, 0.3x4200x6 =0.02L+ 0.02x4200x14
參考: myself
2007-04-25 3:56 am
By conservation of energy
energy to melt 0.02kg of ice+energy required to raise 0.02 kg of water at 0 度to 14度=energy released by 0.3kg from 20度 to 14度raise
m1 *Lv=m1*c *delta T=m2 *c *delta T
0.02L+ 0.02x4200x14= 0.3x4200x6
答案係E
energy to melt 0.02kg of ice+energy required to raise 0.02 kg of water at 0 度to 14度=energy released by 0.3kg from 20度 to 14度raise
m1 *Lv=m1*c *delta T=m2 *c *delta T
0.02L+ 0.02x4200x14= 0.3x4200x6
答案係E
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