Final answer:
A coffee-cup calorimeter is a tool used in chemistry experiments to measure the heat released or absorbed during a chemical reaction. It consists of two Styrofoam cups nested and sealed with an insulated stopper to isolate the system from the surroundings. This type of calorimeter allows for some heat exchange with the outside environment, resulting in less accurate energy values.
Step-by-step explanation:
The tool you are describing, that looks like a sake cup with a lid, is called a calorimeter. It is used in chemistry experiments to measure the heat released or absorbed during a chemical reaction. Specifically, the type of calorimeter you are referring to is a coffee-cup calorimeter.
A coffee-cup calorimeter consists of two Styrofoam cups nested and sealed with an insulated stopper to thermally isolate the system from the surroundings. This type of calorimeter is commonly used in general chemistry labs because it is relatively inexpensive and easy to use. It allows for some heat exchange with the outside environment, which results in less accurate energy values.
The purpose of a coffee-cup calorimeter is to heat small amounts of chemicals to high temperatures while minimizing heat loss to the surroundings, allowing for accurate measurement of the heat exchange during a reaction. It is a crucial tool in thermochemistry and helps scientists understand the energy changes that occur in chemical reactions.