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Another example of thermal decomposition is 2Pb(NO 3) 2 → 2PbO + O 2 + 4NO 2. Some oxides, especially of weakly electropositive metals decompose when heated to high enough temperature. A classical example is the decomposition of mercuric oxide to give oxygen and mercury metal.
Sodium carbonate is obtained as three hydrates and as the anhydrous salt: sodium carbonate decahydrate , Na 2 CO 3 ·10H 2 O, which readily effloresces to form the monohydrate. sodium carbonate heptahydrate (not known in mineral form), Na 2 CO 3 ·7H 2 O. sodium carbonate monohydrate (thermonatrite), Na 2 CO 3 ·H 2 O. Also known as crystal ...
A key step in this process is the reduction of sodium sulfate with coal: [3] Na 2 SO 4 + 2 C → Na 2 S + 2 CO 2. The Na 2 S is then treated with calcium carbonate to give sodium carbonate, a commodity chemical. Recently, development of the 'MagSonic' carbothermic magnesium process has restarted interest in its chemistry: [4] MgO + C ↔ Mg + CO
Calcination is thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O 2 fraction of air), generally for the purpose of removing impurities or volatile substances and/or to incur thermal decomposition.
Tammann temperature was pioneered by German astronomer, solid-state chemistry, and physics professor Gustav Tammann in the first half of the 20th century. [1]: 152 He had considered a lattice motion very important for the reactivity of matter and quantified his theory by calculating a ratio of the given material temperatures at solid-liquid phases at absolute temperatures.
Salt metathesis is often employed to obtain salts that are soluble in organic solvents. Illustrative is the conversion of sodium perrhenate to the tetrabutylammonium salt: [2] NaReO 4 + N(C 4 H 9) 4 Cl → N(C 4 H 9) 4 [ReO 4] + NaCl. The tetrabutylammonium salt precipitates from the aqueous solution. It is soluble in dichloromethane.
Sodium bicarbonate: Solid NaHCO 3: −950.8 Sodium carbonate: Solid Na 2 CO 3: −1130.77 Sodium chloride: Aqueous NaCl −407.27 Sodium chloride: Solid NaCl −411.12 Sodium chloride: Liquid NaCl −385.92 Sodium chloride: Gas NaCl −181.42 Sodium chlorate: Solid NaClO 3: −365.4 Sodium fluoride: Solid NaF −569.0 Sodium hydroxide: Aqueous ...
The following equation is an example, where M represents the given metal: MCO 3 → MO + CO 2. A specific example is that involving calcium carbonate: CaCO 3 → CaO + CO 2. Metal chlorates also decompose when heated. In this type of decomposition reaction, a metal chloride and oxygen gas are the products.