Is a coffee cup calorimeter a constant volume calorimeter?

Yes, a coffee cup calorimeter is considered a constant pressure calorimeter rather than a constant volume calorimeter. It typically consists of two cups, with an insulating layer between them, allowing for reactions or processes to occur at atmospheric pressure while maintaining a relatively constant temperature. The calorimeter measures the heat exchanged during a reaction at constant pressure, which is reflected in the temperature change of the water inside.