Question

NAME EXPT. E-Reactions DATA SHEET: (1) Did your upper lip area feel warmer or cooler? (2) Was the stretching process endothermic or exothermic for the rubber band? (3) Explain your reasoning. teaspoons Amount of NaHCO3 used measured out. (4a) Observations on Sodium Bicarbonate (46) Is sodium bicarbonate water soluble? (5) Observations on Acetic Acid (vinegar) solution (6) Observations after the addition of the first tablespoon of vinegar to the sodium bicarbonate

Answer 1

Answer 1:

Part1: The upper lip felt warmer. A stretched rubber band feels warm against the upper lip.

part2: Since it felt farm against the lip, it means that hear is released in the process of stretching a rubber against the upper lip. Thus, it is an exothermic process as heat is released. But for rubber band, the band feels cooler, thus heat is absorbed by it, therefore for the band it is endothermic process.

Part3: The reason is that endothermic or exothermic depends on wetwhet heat is absorbed or released. Against the lip it felt warmer thus, heat is released and it is exothermic. That is the reasoning as told in part 2 also.

Also sodium bicarbonate is moderately soluble in water.