Self-sealing bag refers to a packaging bag that does not need to be automatically sealed with any tools. Common types include clip type and self-adhesive type. This refers to clip-type self-sealing bags. Because of its low price, good transparency, good air tightness, The clip chain is suitable for tightness, easy to operate, etc., and it allows students to better "touch" the medicine, bringing more sensory stimulation, and has recently become more and more favored by chemistry teachers. Since it is more convenient to conduct liquid-liquid reaction tests in test tubes, if there are solids involved in the reaction, there is no advantage in using test tubes. Consider exploring in a ziplock bag.
For example, sodium carbonate in sewage can combine with water to form crystalline hydrate and release heat. The amount of water in the test should not be too much or too little. The heat released by hydration in this test is not much, and the value of the test tube wall is relatively small. Thick, so difficult to dry. There are obvious advantages to carry out this experiment in a ziplock bag. Gently rub it with your hands from the outside of the ziplock bag to sense the temperature change. It can be felt that the addition of water to the countless sodium carbonate is obviously exothermic.
