Final answer:
The reactions in an isothermal, liquid phase, semi-batch reactor occur at a constant temperature, a characteristic of an isothermal process where phase changes can occur without temperature variation thanks to energy being used to break intermolecular bonds rather than to raise temperature.
Step-by-step explanation:
The question pertains to the thermodynamic processes involved in reactions taking place in an isothermal, liquid phase, semi-batch reactor. An isothermal process is one where the system's temperature remains constant throughout the reaction. This implies that the temperature does not change even when the reaction system undergoes phase changes. For example, when ice melts to water or water boils to steam, the temperature remains at 0°C and 100°C, respectively, during the entire phase change process. This is because the energy added is used to break intermolecular forces rather than to increase the system's temperature. In such reactions, maintaining a constant temperature can be achieved either by controlling the heat exchange meticulously or by having the system in contact with a large heat reservoir that ensures a stable temperature even as heat is absorbed or released by the system.