|
Correct Answer: constant-volume calorimeter
a bomb calorimeter is classified as a constant-volume calorimeter. this designation is crucial because it highlights the fundamental operational principle of the device, namely maintaining a constant volume during the measurement process.
the term "bomb" in "bomb calorimeter" refers to the strong, sealed container used in the calorimeter. this container is designed to withstand the high pressure produced during the combustion of a sample material, which is typically placed inside the bomb along with a known amount of oxygen. the bomb itself is submerged in water within the outer container of the calorimeter.
when the sample is ignited (usually via an electric ignition mechanism), it burns completely, and the heat released from the combustion raises the temperature of the water surrounding the bomb. since the volume of the bomb does not change during the experiment (it is a rigid, sealed container), any heat exchange corresponds solely to changes in temperature, not volume.
the primary measurement taken from a bomb calorimeter is the change in temperature of the water bath, which is directly related to the heat of the reaction. this temperature change, together with the known heat capacity of the water and the calorimeter system, allows for the calculation of the energy content of the original sample.
it is important to note that because the calorimeter operates at constant volume, any gases produced during the reaction (which could potentially increase pressure) do not affect the volume of the system. this characteristic differentiates constant-volume calorimeters from other types such as constant-pressure calorimeters, where the pressure remains fixed but the volume may change.
bomb calorimeters are particularly useful in fields such as food science, biochemistry, and materials science, where understanding the energy characteristics of substances is crucial. they help in determining the calorific value of food, the energy content of fuels, or the stability of materials under conditions of combustion.
|
