File:22. Ендотермна реакција.ogv
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Македонски: Во лабораториска чаша се ставаат претходно иситнети (одделно) бариум хидроксид октахидрат и амониум тиоцијанат. Чашата се става на влажна табла од полистирен. Супстанците се мешаат со стаклено стапче. По кратко време се подига чашата, а со неа се подига и полистиренската подлога (и товарот поставен на неа). Реакцијата е толку ендотермна, што доведува до замрзнување на водата меѓу чашата и таблата. Еден од продуктите на оваа реакција е гасовит амонијак, па при доближување на шишенце со концентрирана хлороводородна киселина (таа емитира гасовит хлороводород), веднаш се забележува чад. Чадот претставува цврст амониум хлорид распределен низ воздух. Равенките на опишаните реакции се:
Ba(OH)2·8H2O(s) + 2NH4SCN(s) = Ba(SCN)2(aq) + 2NH3(g) + 10H2O(l) NH3(g) + HCl(g) = NH4Cl(s) Осмислено и изведено од Марина Стојановска, Миха Буклески и Владимир Петрушевски, Институт за хемија, ПМФ, УКИМ, Скопје.English: Barium hydroxide octahydrate and ammonium thiocyanate previously ground independently are added to a dry beaker. The beaker is placed on a wet block of Styrofoam. The substances are mixed with a glass rod. After a while, an attempt to raise the beaker shows that the block is sealed to the glass. The chemical reaction is so endothermic that the water freezes, and “glues” the glass and the block. A product of the reaction is gaseous ammonia (evident through the formation of smoke when an open bottle with concentrated hydrochloric acid is approached to the beaker). The smoke is finely dispersed ammonium chloride. The reaction equations are the following:
Ba(OH)2·8H2O(s) + 2NH4SCN(s) = Ba(SCN)2(aq) + 2NH3(g) + 10H2O(l) NH3(g) + HCl(g) = NH4Cl(s) Planned and performed by Marina Stojanovska, Miha Bukleski and Vladimir Petruševski, Department of Chemistry, FNSM, Ss. Cyril and Methodius University, Skopje, Macedonia. |
| Date | |
| Source | Own work |
| Author | Карас Студио |
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 12:28, 22 February 2020 | 1 min 1 s, 1,920 × 1,080 (47.12 MB) | Инокентиј | User created page with UploadWizard |
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