Answer:
a thermometer
Step-by-step explanation:
The apparatus that will help Jill to monitor the temperature change of the reaction would be a thermometer.
A thermometer is an instrument used in the measurement of temperature or temperature gradients across two regions.
A typical thermometer consists of 2 elements, namely;
- A sensor that responds to temperature changes, and
- A scale or graduation that is used to measure the temperature changes.
As the sensor responds to changes in temperature, the magnitude of change is indicated on the scale and this magnitude is what is recorded as the temperature of a body of a system.