Final answer:
To determine the quantity of ice needed to cool 600 mL of boiling-hot coffee to 71°C, we need to calculate the heat transfer from the hot coffee to the ice using the specific heat of the coffee and ice, the enthalpy of fusion for water, and the desired temperature change.
Step-by-step explanation:
To determine how much −5°C ice is needed to cool 600 mL of boiling-hot coffee to a more drinkable 71°C, we need to use the principles of heat transfer. The amount of heat that needs to be removed from the coffee to cool it to 71°C can be calculated using the coffee's specific heat, its mass, and the temperature change. The ice will absorb this heat as it melts and warms up to 0°C, and further heat as it warms from 0°C to the final temperature of the coffee. Using the specific heat of ice, the specific heat of water, and the enthalpy of fusion for water, we can calculate the total mass of ice needed.
To calculate the exact amount of ice required, you would need to set the heat lost by the coffee equal to the heat gained by the ice and the resultant water until thermal equilibrium is achieved. Since the coffee would initially be at boiling point (100°C), the calculation would involve the following steps: calculating the energy required to cool the coffee from 100°C to 71°C, calculating the energy required to convert ice at −5°C to water at 0°C, and then the amount of heat the resulting water can absorb up to 71°C. Unfortunately, without the exact specific heat values and the enthalpy of fusion of ice in the question data, an exact numerical solution can't be provided here.