Jill is studying the temperature output of an ammonium chloride hand warmer. What apparatus will best help her monitor the temperature change of the reaction?

a thermometer

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;

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.

answer; i believe the answer is hydraulic action;

i don't know, but does anyone wanna be friends? i'm doing my homework at 1: 49 in the morning : /