1 kg of ice at 0∘C is mixed with 1 kg of steam at 100∘C. What will be the composition of the system when thermal equilibrium is reached? Latent heat of fusion of ice = 3.36 × 105 J kg−1 and latent heat of vaporization of water = 2.26 × 106 J kg−1
665 gm steam, 1.335 kg water
As the mass of ice and steam is the same, let us start by assuming that all the ice converts to water at 0°C, then heats up to water at 100∘C, in the process converting some of the steam to water at 100∘C. Don't worry, if our assumption is incorrect, the mass of water will come out negative and we can then consider other possibilities!
So, Heat gained during ice at 0∘C → water at 100∘C
Q1 = mL1 + msΔT
m = 1kg
L1 → Latent heat of fusion
ΔT = 100∘C
S→ specific heat of water
⇒ Q1 = L1 + 100S
Now, heat released by x kg steam converted to water at → is
Q2 = xL2
Where, L2→ latent heat of vaporization
But, Q1 = Q2
L1 + 100 S = xL2
⇒ x = L1 + 100sL2
⇒ x = 0.335 kg steam converts to water
∴ Amount of steam left = 1 − 0.335 = 0.665 kg