Final answer:
To determine the final temperature of coffee that has undergone evaporation, the heat of vaporization and the specific heat of water must be considered in the calculation.
Step-by-step explanation:
When coffee initially at 90.0°C loses 2.00 g through evaporation, the temperature of the remaining 250 g of coffee will decrease. This is because the evaporation process consumes a significant amount of heat energy, known as the heat of vaporization.
The calculation for the final temperature would involve the heat of vaporization of water, the mass of the coffee that evaporated, and the specific heat of water (assuming that coffee shares similar thermal properties with water). However, precise calculations would be required to determine the exact final temperature of the coffee.