Example Problem - Heat Capacity (2) - "The Coffee Problem"

John, like most people in the STEM fields, has an unhealthy addiction to caffeine but he can totally quit whenever he wants. He just doesn’t want to. Anyway, let’s say he gets up in the morning and brews a fresh pot of coffee, and pours 16 oz (473.2 mL) into a well-insulated thermos to bring along to his 8:00 AM class. When it is poured, the coffee is about 94°C, which is way too hot for John to drink; meaning he often goes into class uncaffeinated, much to the detriment of his students.

He decides to add ice to the coffee, which quickly drops the temperature to a much more reasonable level. John’s freezer keeps his ice cubes at around -5°C, and they come out of the tray in 1" x 1" x 2" chunks called “cubes” (despite not being cube shaped). The latent heat of fusion of ice at 1 atm is 334 kJ/kg, and the density and specific heat capacity of ice at ~-5°C are 917.5 kg/m^3 and 2.06 kJ/kg⋅K, respectively.

How many whole ice cubes should John add to ensure that his coffee reaches an equilibrium temperature as close to 60°C as possible?