{"product_id":"endothermic-ice-packs","title":"Endothermic Ice Packs","description":"\u003cdiv class=\"description\"\u003eCrack a commercial instant cold pack and it gets cold. But why? This experiment puts the answer in your hands. Dissolve urea in water and feel the cup get noticeably cold as the crystal structure absorbs heat from its surroundings. This is the same endothermic chemistry used in sports medicine cold packs, emergency first-aid kits, and agricultural cooling applications worldwide. Build your own working cold pack in a zip-lock bag and hold it against your wrist. Then go further: measure the temperature drop precisely with a calorimeter, calculate the enthalpy of dissolution from your data, and compare it to the published literature value of +15.4 kJ\/mol. Pair it with the Sodium Acetate Hot Ice kit for a head-to-head thermodynamics showdown. One crystal heats up, the other cools down, and the same Gibbs free energy equation explains both. This is quantitative chemistry with a result you can feel in your hands.\u003c\/div\u003e\n\u003cdiv class=\"copy-grid\"\u003e\n\u003cdiv class=\"copy-section\"\u003e\n\u003ch4\u003e\u003c\/h4\u003e\n\u003ch4\u003eWhat's Included\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eUrea CO(NH₂)₂ ~90g — non-regulated, ships ground and air\u003c\/li\u003e\n\u003cli\u003eStyrofoam cups × 6 (nested calorimeter)\u003c\/li\u003e\n\u003cli\u003eThermometer\u003c\/li\u003e\n\u003cli\u003eGlass stirring rod\u003c\/li\u003e\n\u003cli\u003eWeigh boats × 3\u003c\/li\u003e\n\u003cli\u003eZip-lock bags × 3 (cold pack demonstration)\u003c\/li\u003e\n\u003cli\u003eNitrile gloves × 2 pairs\u003c\/li\u003e\n\u003cli\u003eSafety goggles × 2 pairs\u003c\/li\u003e\n\u003cli\u003eFull-color printed worksheet with calorimetry calculations\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"copy-section\"\u003e\n\u003ch4\u003eCurriculum Connections\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eNGSS HS-PS3-1\/4 — Calorimetry and enthalpy measurement\u003c\/li\u003e\n\u003cli\u003eAP Chemistry Units 3 \u0026amp; 6 — Hydrogen bonding, thermodynamics, q=mcΔT\u003c\/li\u003e\n\u003cli\u003eIB Chemistry Topics 4, 5 \u0026amp; 15 — IMF, energetics, Hess's Law\u003c\/li\u003e\n\u003cli\u003eCommon Core HSN-Q.A.1 — Unit conversion, percent error calculation\u003c\/li\u003e\n\u003cli\u003eReal-world: instant cold packs, sports medicine, agricultural cooling, cosmetics\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"copy-section\"\u003e\n\u003ch4\u003e♻ Waste Disposal\u003c\/h4\u003e\n\u003cdiv\u003e\u003cstrong\u003eRating: Easy\u003c\/strong\u003e\u003c\/div\u003e\n\u003cdiv\u003eUrea is completely non-hazardous and biodegradable. Dissolve in water and drain freely.  No special disposal required whatsoever. One of the safest waste streams in the entire series.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"The Alchemist Experience","offers":[{"title":"Default Title","offer_id":52045864239386,"sku":null,"price":0.0,"currency_code":"USD","in_stock":false}],"url":"https:\/\/thealchemistexperience.shop\/products\/endothermic-ice-packs","provider":"The Alchemist Experience","version":"1.0","type":"link"}