Most cold packs utilize water and ammonium chloride or ammonium nitrate to create endothermic reactions. Endothermic reactions require energy and obtain it by absorbing heat from the environment.Know More
While the majority of commercial cold packs use ammonium nitrate or ammonium chloride, many types of salts create endothermic reactions. Instant cold packs maintain water and ammonium salt in separate sections, with a thin barrier in-between. Breaking the barrier allows the salt and water to mix, dissolving the salt. As the ammonium salt dissolves, it absorbs heat from the air around it, lowering the temperature of the water to its freezing point. Once the water reaches its freezing point, it becomes less effective at dissolving the salt, meaning that some salt remains. Eventually the water begins to warm, allowing more salt to dissolve and then cooling the water again. In this way, cold packs retain their cool temperature for an extended period of time.
Endothermic reactions do not just occur in cold packs. Mixing an acid, such as vinegar or citric acid, with baking soda, a base, absorbs heat and cools its container for a short amount of time. Because endothermic reactions are those that absorb energy rather than releasing it, photosynthesis is also an endothermic reaction as it requires the absorption of energy in the form of sunlight.Learn more about Chemistry
Lemonade is a mixture because sugar, water and lemons are combined together without a chemical reaction taking place. The bonds of the substances can't combine with one another, instead the three items are mixed up.Full Answer >
A burning candle is an example of a chemical change because the paraffin wax, which is a hydrocarbon, undergoes a chemical reaction with oxygen to form water and carbon dioxide gas. Because the chemical structure of the paraffin has been altered, this is a chemical change.Full Answer >
Tannerite is a binary compound explosive that consists of ammonium nitrate and aluminum powder. The ammonium nitrate component provides the fuel for the explosive, and the aluminum powder acts as a catalyst. The compound is stable under normal conditions, and because it ships as two components that are not independently explosive, no special permits or restrictions apply to its handling.Full Answer >
Barium carbonate is soluble in hydrochloric acid, nitric acid, acetic acid, ammonium chloride and ammonium nitrate. It is slightly soluble in water but insoluble in sulfuric acid and ethanol.Full Answer >