Phy heat question

2008-10-08 4:49 am
0.1 kg of a mixture of ice and water is placed in a polystyrene cup. When 0.15 kg of water at 40 degree celsius is added, the resulting temperature is 10 degree celsius. Find the mass of ice in the mixture.

回答 (1)

2008-10-08 8:24 am
✔ 最佳答案

Specific latent heat of fusion of ice, L = 334000 J kg-1
Specific heat capacity of water, c = 4200 J kg oC-1

Let m kg be the mass of ice in 0.1 kg of the mixture of ice and water.
Let 0oC be the initial temperature of the mixture of ice and water.

Heat absorbed for (0oC ice → 0oC water → 10oC water)
= mL + mc∆T
= m(334000) + 0.1(4200)(10 - 0)
= (334000m + 4200) J

Heat released for (40oC water → 10oC water)
= mc∆T
= (0.15)(4200)(40 - 10)
= 18900 J

Assume that there is no heat loss to the surroundings.
Heat absorbed = Heat released
334000m + 4200 = 18900
334000m = 14700
m = 0.044 kg

Mass of ice in the mixture = 0.044 kg
=


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