A spirometer can be used to measure the rate of oxygen consumption in a human subject. The subject breathes in and out through a mouthpiece connected to a sealed chamber filled with oxygen. To ensure that the decrease in the volume of gas in the chamber is solely due to the volume of oxygen consumed, the carbon dioxide exhaled by the subject must be removed from the system.
State the name of a chemical substance that is placed inside the spirometer to absorb this carbon dioxide.
