Step 1: Identifying the known and unknown
Given,
Mass of ice, m1=2 kg
Mass of water, m
Initial temperature of water,
T1=100∘C=373 K
Final temperature of water,
T2=0∘C=273 K
Specific heat capacity of water,
c=4200 J kg−1 K−1
Specific latent heat of ice,
L=336×103 J kg−1
Step 2: Calculate the amount of heat required to convert ice into water at 0∘C
Specific latent heat,
L=Qm1(at T=0∘C)
⇒Q= m1L
Therefore,
Qice=(2 kg)×(336000 J kg−1)
Qice=672000 J
Step 3: Calculate the amount of heat released by hot water to lower its temperature to 0∘C
Specific heat capacity, c=Q|m×ΔT|
⇒Q=mc|ΔT|
|ΔT|=|T2−T1|
|ΔT|=| 273 K−373 K|=100 K
Therefore,
Qwater=(m)×(4200 J kg−1 K−1)×(100 K)
⇒Qwater=420000m J
Step 4: Calculation of mass
According to the principle of calorimetry,
Qwater=Qice
420000m J=672000J
m=672000420000
m=1.6 kg
The mass of water used was 1.6 kg.