During an experiment, Mr. Lehman tells his students to be alert for signs that an endothermic reaction is happening. Which of the following scenarios would his students most likely observe?

The correct answer for the question that is being presented above is this one: "A test tube becomes cool to the touch." During an experiment, Mr. Lehman tells his students to be alert for signs that an endothermic reaction is happening. The student will most likely observed that the test tube becomes cool to the touch.