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Coolest Demo of the School Year Table I shows us 25 chemical reactions and physical changes, and the Δ H for each of them. When Δ H is a negative number, the reaction is exothermic. When Δ H is a positive number, the reaction is endothermic
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Coolest Demo of the School Year Table I shows us 25 chemical reactions and physical changes, and the ΔH for each of them. When ΔH is a negative number, the reaction is exothermic. When ΔH is a positive number, the reaction is endothermic Most of the reactions we have seen this year are exothermic, they are much more common in our class. Today is different. This is a funky reaction, not one of the five we have learned, but we can still balance it. We will just look now.
20.0 grams Barium hydroxide octahydrate solid Ba(OH)2▪8H2O(S) will be combined with 10.0 grams Ammonium thiocyanate solid NH4SCN(S) Ba(OH)2▪8H2O(S) + NH4SCN(S) → Ba(SCN)2(AQ) + 2NH3(G) + 10H2O(L) The ammonia gas produced will irritate your nose if you breathe too much of it, so watch out! Smile, this is very unusual.
Stir the two solids together in a 250 mL beaker. Watch out for the ammonia gas. Note the temperature change. Some water, for effect.