A simple calorimeter is used to determine the enthalpy change of reactions in dilute water solution. In a simple calorimeter, heat (Q) exchanged by the system and the calorimeter is equal to the enthalpy change of the system (△H). This occurs under the condition of
Question 8 options:
a) constant concentration
b) constant heating
c) constant volume
d) constant pressure
e) constant temperature
e) constant temperature
The correct answer is e) constant temperature.
In a simple calorimeter, the heat exchanged by the system and the calorimeter is equal to the enthalpy change of the system (delta H). This is because the calorimeter measures the heat absorbed or released by the system during a reaction.
To achieve constant temperature in the calorimeter, it is important to ensure that no heat is lost or gained to or from the surroundings. This can be achieved by insulating the calorimeter to minimize heat transfer with the surrounding environment.
If the calorimeter is not well-insulated, heat may be lost or gained to the surroundings, resulting in inaccurate measurements. To minimize heat loss or gain, a lid is usually placed on the calorimeter, and the calorimeter is often placed inside a larger container filled with a known volume of water, which helps in maintaining a constant temperature during the reaction.
By maintaining a constant temperature, any heat transferred from the system to the calorimeter can be accurately measured, allowing us to determine the enthalpy change of the system.
Therefore, the condition needed for a simple calorimeter to accurately measure the enthalpy change of a system is constant temperature (option e).