Final answer:
The equilibrium temperature of the system is 7.5°C. No unmelted ice is present at equilibrium.
Step-by-step explanation:
To find the equilibrium temperature of the system, we can use the principle of conservation of energy. The heat gained by the water is equal to the heat lost by the ice cubes. Let's calculate the heat gained by the water first:
Q = mcΔT = (0.800 kg)(4186 J/kg·°C)(T_f - 21.5°C)
where m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. Similarly, the heat lost by the ice cubes is:
Q = mcΔT = (3 × 107.0 g)(2.062 J/g·°C)(T_f - 0°C)
Setting these two equations equal to each other and solving for T_f, we get:
T_f = 7.5°C
For part (b), to determine if there is any unmelted ice at equilibrium, we need to calculate the amount of heat required to melt the ice cubes:
Q = mi_Lf
where mi is the mass of the ice and Lf is the latent heat of fusion. If the amount of heat gained by the water (calculated earlier) is greater than the heat required to melt the ice, then there will be no unmelted ice at equilibrium.
In this case, since the heat gained by the water is greater than the heat required to melt the ice, there is no unmelted ice at equilibrium.