Question

what happens to the temperature of the water in a coffee - cup calorimeter when an endothermic reaction occurs?
the temperature of the water decreases.
the temperature of the water increases.
the temperature of the water remains the same.
the temperature of the water fluctuates.

Explanation:

In an endothermic reaction, heat is absorbed from the surroundings. In a coffee - cup calorimeter, the water is part of the surroundings. When heat is absorbed by the reaction, the heat content of the water (which is related to its temperature) decreases because the reaction is taking in heat from the water.

Answer:

The temperature of the water decreases.