Making ammonia sim
Heat the dry mixture: 2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2NH₃ + 2H₂O.
Making ammonia · covers the GCSE, IGCSE, O-Level topic
What the sim shows
Heat the dry mixture: 2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2NH₃ + 2H₂O. The test tube slopes down at the mouth: water made in the reaction condenses on the cool glass near the mouth, and it runs out towards the bung instead of back onto the hot glass, which could crack. The gas is dried by calcium oxide. Concentrated sulfuric acid would neutralise the ammonia to ammonium sulfate, and anhydrous calcium chloride combines with it, so with either one nothing reaches the jar (the acid is shown soaked into pumice in the same tower; it is usually held in a wash bottle, and takes the ammonia either way). Ammonia is less dense than air (Mᵣ 17 against about 29), so it is collected by upward delivery into an inverted jar. It cannot go over water: it is extremely soluble, and dissolves. Damp red litmus at the mouth turns blue when the jar is full. Volumes are at r.t.p., 24 dm³ per mole. The heating rate and the air in the apparatus (65 cm³) are the desk's estimates, and the jar is taken to fill as a sharp front pushing the air out (plug flow); a real jar mixes a little, so the litmus turns a little early. The clock runs 6 times faster than real time.
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