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The Calorimeters Calorimeters are a device that can measure the heat that comes from burning an item. Simple Calorimeter A simple calorimeter is used to detect the enthalpy change when a fuel is burned. The fuel is burnt to heat a specific mass of water and then measure its rise in temperature. The word calorimeter comes from the Latin phrase calor which means heat. A simple calorimeter just consists of a thermometer attached to a metal container full of water suspended above a combustion chamber. Below is a diagram of a simple calorimeter.
The temperature of the water allows for calculating calorie content of the fuel. Pressurized with pure oxygen and containing a known mass of a sample and a small amount of water, it is submerged under a known volume of water before the charge is electrically ignited. The bomb, with the sample and oxygen, form a closed system, no air escapes during the reaction. The energy released by the combustion raises the temperature of the steel bomb, its contents, and the surrounding water jacket. The temperature change in the water is then accurately measured.
This temperature rise, along with a bomb factor (which is dependent on the heat capacity of the metal bomb parts) is used to calculate the energy given out by the sample burn. A small correction is made to account for the electrical energy input, the burning fuse, and acid production (by titration of the residual liquid). After the temperature rise has been measured, the excess pressure in the bomb is released. Basically, a bomb calorimeter consists of a small cup to contain the sample, oxygen, a stainless steel bomb, water, a stirrer, a thermometer and ignition circuit connected to the bomb. Below is a diagram of a bomb calorimeter.