Endothermic reactions are accompanied by the absorption of heat. The dissolving of ammonium nitrate in water is an example of an endothermic reaction. The solution resulting from this mixture is colder than either the ammonium nitrate or the water. This is the simple explanation of what happens in an instant ice pack. The more detailed information will be discussed in the following paragraphs. Cold Packs
Most cold packs come with a fabric cover made to absorb condensation and to protect the skin from contacting the surface of the cold pack. Cold packs are used for injury or muscle relief. The cold pack contains two bags one containing water and the other containing ammonium chloride. Once the ammonium chloride is broken it reacts with water causing a endothermic reaction. Cold packs remain cold for different lengths of time through the reaction extending up to fifth teen minutes precession, giving users relief from inflammation and pain at the site of injury. Many cold packs are reusable, by refreezing the e pack. Once the pack is refrozen it contains stability in the reaction. It can then be reapplied to the injury causing an endothermic reaction giving comfort to the surrounding area. Cold Pack Reactions
Cold packs have a endothermic reaction that usually contains water and a packet of ammonium chloride. The Cold pack is activated by breaking the barrier separating the water and ammonium allowing the chemicals to mix. Once the cold pack is placed to the skin, energy is released keeping the cold pack reacting for a period of time. Endothermic reaction absorbs heat causing the cold pack to keep reacting until the cool of the pack is warm up to the surrounding area. Endothermic reaction is the opposite of exothermic reaction absorbing the surrounding heat. When the ammonium chloride reacts with water it has a chemical reaction that will give off a cold effect, when soaking up heat from the body. How Cold Packs Work
The cold packs have...