Question

what is kept constant in the coffee - cup calorimeter?
volume
pressure
temperature
heat

Explanation:

A coffee - cup calorimeter is an open - air device. In an open - air environment, the pressure is equal to the atmospheric pressure and remains constant throughout the experiment. Volume can change (for example, if a gas is produced in a reaction), temperature changes as heat is absorbed or released in the reaction, and heat is either absorbed or released (not kept constant).

Answer:

Pressure